G1 done: Saved Pages read offline, checked by hand

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT

.gitignore

@@ -1,3 +1,11 @@
 .pio/
 .vscode/
 *.pyc
+
+# Private signing keys never belong in the repository (ADR 0003)
+*key.pem
+
+# Generated by pioarduino's hybrid compile from custom_sdkconfig (platformio.ini)
+.dummy/
+managed_components/
+sdkconfig.*

CONTEXT.md

@@ -40,6 +40,26 @@ _Avoid_: DM (in docs), private message
 Rebroadcasting another Node's packet so it travels further across the mesh.
 _Avoid_: forwarding, repeating
 
+**Capsule**:
+A Gemini site: everything served by one host on Geminispace.
+_Avoid_: site, server (when the content is meant)
+
+**Saved Page**:
+A Gemini page kept on the SD card to read offline, with the URL it came from and when it was saved. Kept until the user deletes it; Storage Clean-up never offers it.
+_Avoid_: cache, download (a download is a non-text file saved from Gemini)
+
+**GNSS Service**:
+The Service that owns the GNSS receiver on the Cap: it reads its NMEA sentences in the background and holds the current Fix, position, time and satellites.
+_Avoid_: GPS (GPS is one constellation among several)
+
+**Fix**:
+What the receiver currently knows: none, 2D (position without altitude) or 3D (with altitude), from how many satellites, at what HDOP.
+_Avoid_: lock, signal
+
+**Track**:
+A route recorded from GNSS positions to a GPX file on the SD card, started and stopped by the user.
+_Avoid_: trace, log (a Log is recorded on its own)
+
 **Wi-Fi Service**:
 The Service that owns the Wi-Fi radio. It's always in exactly one mode: *Off*, *Connected* (joined to a Saved Network) or *Monitoring* (passively observing). When Wi-Fi is enabled in Settings, it stays Connected whenever a Saved Network is in range. It goes Monitoring only while Wi-Fi Tools needs it, then reconnects.
 _Avoid_: network manager
@@ -49,7 +69,7 @@ A Wi-Fi network the device may join on its own (name, password). When several ar
 _Avoid_: profile, known network
 
 **IRC Service**:
-The Service that keeps the IRC connection alive in the background once the IRC App has started it, until the user disconnects. It reconnects after drops, and pauses while the Wi-Fi Service is Monitoring. It does not start by itself after a reboot.
+The Service that keeps the IRC connection alive in the background once the IRC App has started it, until the user stops it (`/quit`, or `irc stop` on the console). Once stopped by hand, opening the App again doesn't reconnect; typing a line does. It reconnects after drops, and pauses while the Wi-Fi Service is Monitoring. It does not start by itself after a reboot.
 _Avoid_: IRC client (that's the App)
 
 **Buffer**:
@@ -104,6 +124,34 @@ The Notification raised once per boot when the SD card passes 80% full. Selectin
 **Storage Clean-up**:
 The screen where the user deletes old Logs and Captures by category and age, with a preview of the space freed. Notes are never offered for deletion.
 
+**Firmware Update**:
+Installing a new firmware image without a USB cable: pushed over Wi-Fi from the developer's PC, or read from the SD card.
+_Avoid_: flash, upgrade (alone)
+
+**Update File**:
+One signed file (`.ota`) that carries a firmware version, its image and a signature. The same file works over Wi-Fi and from the SD card. Anything not signed with the project's key is refused.
+_Avoid_: binary, bin
+
+**Probation**:
+The state of newly installed firmware until it proves healthy: booted, UI drawn, Services started, 30 s without a crash, and Wi-Fi connected if it's configured. Then it's confirmed for good.
+_Avoid_: trial, test mode
+
+**Rollback**:
+Returning automatically to the previous firmware when new firmware resets or crashes during Probation.
+_Avoid_: revert, downgrade (a downgrade is installing an older version on purpose)
+
+**Safe Mode**:
+What the firmware starts instead of everything else after 3 crash restarts in a row: Wi-Fi and Firmware Updates (and the Debug Console in a Debug Build), so it can be fixed without a cable. A normal restart leaves it.
+_Avoid_: recovery mode, failsafe
+
+**Debug Build**:
+A firmware built with the remote debugging aids compiled in (`+debug` in its version). Release builds have none of them.
+_Avoid_: dev build, test build (a test build is one made to fail on purpose, such as a crashing update)
+
+**Debug Console**:
+The console of a Debug Build over Wi-Fi: live log lines and the serial commands, behind a token.
+_Avoid_: telnet, remote shell
+
 ## Relationships
 
 - The **Launcher** starts **Apps**. Exactly one **App** is in the foreground.
@@ -114,6 +162,8 @@ The screen where the user deletes old Logs and Captures by category and age, wit
 - A **Sweep** pauses the **Mesh Service**; a **Sniffer** does not.
 - Every transmission is bounded by the **Region** and its **Duty Cycle Budget**.
 - Past 90% SD usage, **Logs** stop being written; the remaining space is kept for **Captures**. Nothing is deleted without the user's confirmation.
+- A **Firmware Update** installs an **Update File**; the new firmware runs on **Probation**, and fails back by **Rollback**.
+- **Rollback** covers new firmware; **Safe Mode** covers confirmed firmware that keeps crashing.
 - A **Node** may be in several **Channels**. A **Direct Message** targets exactly one **Node**.
 
 ## Flagged ambiguities

README.md

@@ -18,6 +18,8 @@ scripts/ci.sh
 
 This runs the host-side unit tests (`test/`, `native` environment), then builds the firmware. The output is `.pio/build/cardputer-adv/firmware.factory.bin`.
 
+The framework is rebuilt with the TLS settings in `platformio.ini` (`custom_sdkconfig`, ADR 0006), so the first build after a fresh checkout takes about 4 minutes; later builds take under a minute.
+
 ## Flash
 
 1. Connect the Cardputer by USB-C.
@@ -37,6 +39,27 @@ This runs the host-side unit tests (`test/`, `native` environment), then builds
 sudo usermod -aG dialout "$USER"
 ```
 
+## Firmware Updates over Wi-Fi (OTA)
+
+Once the Cardputer runs an OTA-capable firmware (flashed once over USB), updates can go over Wi-Fi:
+
+```sh
+scripts/ota_keygen.sh                  # once: creates the signing key (see ADR 0003)
+scripts/flash.sh --ota 10.39.39.12     # build, sign and push; or set RORO_OTA_HOST
+```
+
+The device shows the push address in **Settings → Firmware**. It installs a correctly signed update right away, restarts (waiting up to 60 s if you're typing), and runs the new firmware on **Probation**. If the new firmware crashes, or can't reconnect Wi-Fi within 3 minutes, it rolls back to the previous one and says so.
+
+To install from the SD card instead, copy the `.ota` file from `.pio/build/cardputer-adv/` into `/updates` on the card, then use **Settings → Firmware**. With the Cardputer on USB, the card can stay in: `scripts/sd_put.sh <file.ota>` sends it over the serial console into `/updates` (about 30 s for 1.6 MB, checked with SHA-256 before it's renamed into place; `SD_PUT_DEBUG=1` shows the console while it runs).
+
+**The private key** lives in `~/.config/roro9stack/ota-key.pem` and must never be committed. If it's lost, generate a new pair and flash once over USB.
+
+## Gemini
+
+The Gemini App browses Geminispace (docs/milestones/G1.md): Tab and Shift+Tab pick a link, Enter follows it, Back returns (to where the page was scrolled), Space pages down, `g` types an address. Certificates are trusted on first use; a changed one stops the page and asks.
+
+On a page, `b` bookmarks it, `s` saves it to the SD card to read offline (a non-text file goes to `/gemini/downloads/`), `S` saves it with the pages it links to on the same capsule (up to 30). The start page lists bookmarks and Saved Pages; inside a Saved Page, `r` refreshes it and `d` deletes it. With a card, every page streams through `/gemini/cache/` so a large one arrives whole even with IRC connected; what doesn't fit in memory stays on the card.
+
 ## Development aids
 
 `scripts/serial_log.sh [seconds] [command…]` records the serial output, and can send commands to the firmware first. For example, `scripts/serial_log.sh 30 short sleep:12 burst` sets short screen timeouts, waits 12 s, then sends a burst of Toasts.
@@ -52,8 +75,48 @@ sudo usermod -aG dialout "$USER"
 | `sd list` | Lists the files of each Storage Clean-up category |
 | `cat <path>` | Prints the first ~1.2 KB of a file on the SD card |
 | `irc start` | Starts the IRC Service (normally done by opening the IRC App) |
+| `irc stop` | Stops it, as `/quit` does: QUIT if connected, no more retries, and the App stays disconnected until you type |
+| `gemini get <url>` | Fetches a Gemini page and prints its header, size, certificate fingerprint and heap use |
+| `gemini trust <host> <port> <sha256>` | Pins a certificate by hand (the Gemini App asks when one changes) |
 | `irc say <buffer> <text>` | Types into a Buffer, commands included (`irc say 0 /join #test`) |
 | `irc dump` | Prints IRC status, memory, and the last lines of each Buffer |
 | `wifi status` | Prints Wi-Fi state, network, signal, clock and free heap |
+| `info` | Firmware, uptime, last start reason, memory, Wi-Fi, and both app slots with their versions and OTA states |
+| `tasks` | FreeRTOS tasks: state, priority, lowest free stack, CPU share |
+| `reboot` / `boot other` | Restart, or restart into the other app slot (a manual Rollback) |
+| `log level <0-5>` | ESP-IDF log level |
+| `ls [folder]` / `rm <path>` | Lists a folder of the SD card, or deletes a file |
+| `install <path>` | Update from SD with that `.ota` file, as Settings → Firmware does |
+| `crash` | The last crash: which firmware, why, task, PC and backtrace (from the core dump in flash) |
+| `coredump erase` | Forgets the core dump |
+| `crash abort` / `crash wdt` | Debug Builds: crash on purpose, or hang the main loop until the watchdog fires |
+| `help` | Lists the commands |
 
 `scripts/flash.sh` stops a running serial log first, since it would hold the port.
+
+### Debug Builds and the Debug Console
+
+`scripts/flash.sh --debug` (USB) or `scripts/flash.sh --debug --ota <ip>` (Wi-Fi) installs a Debug Build: the same firmware plus the Debug Console on TCP 2323 (ADR 0004). Then, with `RORO_OTA_HOST` set to the device's IP:
+
+```sh
+scripts/rdbg.py                 # interactive: the console backlog, live lines, and commands
+scripts/rdbg.py info            # one command and its reply
+scripts/rdbg.py -b tasks        # the same, after the backlog (boot messages and so on)
+```
+
+Every command above works there too, plus a few handled by the PC side or the console's own task:
+
+```sh
+scripts/rdbg.py crash           # the last crash, its backtrace decoded against that exact build's ELF
+scripts/rdbg.py coredump        # fetch the core dump and decode it all (registers, every task) with esp-coredump
+scripts/rdbg.py reset           # restart at once, even if the main loop is stuck
+scripts/rdbg.py screenshot      # the screen as a PNG (2x)
+scripts/rdbg.py put <file> [card path]    # to the SD card (default /updates/<name>), SHA-256 checked, ~300 KB/s
+scripts/rdbg.py get <card path> [file]    # from the SD card
+```
+
+So a Firmware Update can also go `rdbg.py put roro9stack-….ota` then `rdbg.py install /updates/roro9stack-….ota`: the Update from SD path, without touching the device.
+
+Every build keeps its ELF in `.pio/elves/` (version and digest in the name) for that; `scripts/decode_backtrace.sh <version|digest> <addresses>` decodes any backtrace by hand.
+
+After 3 crash restarts in a row the firmware starts in **Safe Mode** (ADR 0005): only Wi-Fi, Firmware Updates and the Debug Console, so a fix can be pushed as usual. `reboot` leaves it. The token is in `~/.config/roro9stack/debug-token`, made by the first build; keep developing on Debug Builds, so the firmware a Rollback returns to always has the console.

default_8MB.csv

@@ -0,0 +1,7 @@
+# Name,   Type, SubType, Offset,  Size, Flags
+nvs,      data, nvs,     0x9000,  0x5000,
+otadata,  data, ota,     0xe000,  0x2000,
+app0,     app,  ota_0,   0x10000, 0x330000,
+app1,     app,  ota_1,   0x340000,0x330000,
+spiffs,   data, spiffs,  0x670000,0x180000,
+coredump, data, coredump,0x7F0000,0x10000,

docs/adr/0001-own-firmware-speaking-meshtastic.md

@@ -9,3 +9,7 @@ A fork would give full compatibility on day one, but its architecture is built a
 - We accept partial Meshtastic compatibility at first: text on channels, Direct Messages, node list, position and relaying.
 - The phone-app (BLE) API and PKI-encrypted Direct Messages are deferred, and we must re-implement protocol details ourselves.
 - Multi-boot with stock Meshtastic via a launcher was rejected: it gives none of our own UX.
+
+## Note (2026-10-04, M2)
+
+NMEA is parsed by our own small, host-tested parser instead of TinyGPSPlus: the GNSS App's Sky view needs the satellite list (GSV) across several constellations, which TinyGPSPlus doesn't track. See docs/milestones/M2.md, Q66.

docs/adr/0003-own-signature-check-not-secure-boot.md

@@ -0,0 +1,12 @@
+# Signed Update Files checked by the firmware, not ESP32 Secure Boot
+
+Firmware Updates are accepted only when their Update File carries a valid ECDSA P-256 signature over the image's SHA-256. The firmware itself checks it, against a public key compiled into it, before switching the boot partition. The private key lives outside the repository, in `~/.config/roro9stack/ota-key.pem`.
+
+We chose this over the ESP32's hardware Secure Boot. Secure Boot is enforced by the chip, but it burns eFuses one-way: a mistake bricks the device, and the device can never run unsigned firmware again, which makes recovery over USB harder. On a single development device, a software check that refuses unsigned pushes is enough, and it stays reversible: a new firmware can carry a new public key.
+
+## Consequences
+
+- Someone with physical USB access can still flash anything. Only Wi-Fi and SD card updates are guarded.
+- **Losing the private key** means the next update has to go over USB, carrying a new public key.
+- P-256 rather than Ed25519, because the firmware's TLS library (mbedTLS) already verifies it, so it costs no extra code.
+- **Rollback: the bootloader first, the firmware as a second line.** Arduino-ESP32 marks a new image valid before `setup()` unless the sketch overrides `verifyRollbackLater()`, which once made every update look good and hid the bootloader's rollback (it had looked like the prebuilt bootloader ignored it). With the override, an image stays pending until Probation confirms it, and the bootloader reverts one that restarts unconfirmed, however early it crashes. The firmware also counts its own boots on Probation, very first thing in `setup()`, and reverts itself on the second unconfirmed start.

docs/adr/0004-debug-console-in-debug-builds.md

@@ -0,0 +1,23 @@
+# A Debug Console over Wi-Fi, in Debug Builds only
+
+The goal of Firmware Updates is to manage the device without a cable, and that includes finding out what went wrong. So a **Debug Build** (`cardputer-adv-debug`, `-DRORO_DEBUG`, version suffix `+debug`) adds a **Debug Console** on TCP 2323: the serial console, over Wi-Fi. A client sends a token as its first line, then gets the last 4 KB of console output (boot messages included), every new line live, and runs the same commands as the serial port, plus a few that only make sense remotely. ESP-IDF's own log lines are teed into it.
+
+It's compiled out of release builds entirely, rather than switched off by a setting. A console that runs commands is a remote control: in a release build, nothing listens.
+
+## How it fits
+
+- **Console, not Serial.** All human-readable output goes through `console`, which writes to the USB port and, in a Debug Build, to a ring buffer the Debug Console drains. Writes never wait for USB: a host that's attached but not reading used to stall the main loop for up to 2 s per line.
+- **Commands run on the main loop.** The socket lives on the Debug Console's own task, which only queues command lines. The main loop runs them, as it does serial commands, so they touch Apps and Services from the one task allowed to.
+- **The token** is 128 random bits in `~/.config/roro9stack/debug-token`, made by the first build and passed into the container. It's never committed; a Debug Build refuses to compile without one. Like the OTA key, it guards against the network, not against someone holding the device.
+- **One client at a time**, to keep memory flat (4 KB for the ring since M2, 6 KB of task stack).
+- **Binary commands are answered on the console's own task**, not queued: `get`/`put` (SD card files, run as one Storage Service job each so card access stays on the storage task, with TCP doing the flow control), `screenshot` (the 32 KB RGB332 frame the UI composes into, read as it stands, so it may tear), `coredump get` and `reset`. These keep working when the main loop is stuck. A failed `put` closes the connection, so the rest of the file is never read as commands.
+
+## Keep a Debug Build in the fallback slot
+
+Rollback returns to the previous firmware, whatever it is. As long as development goes through Debug Builds, the firmware a crash falls back to has the Debug Console, so a bad update never costs remote access. A release build pushed over a Debug Build leaves the Debug Build in the other slot until the next update overwrites it.
+
+## Consequences
+
+- Anyone on the same network with the token can read the console, inject keys and reboot the device. The console never prints stored secrets (Wi-Fi and IRC passwords), but the IRC traffic it shows is readable.
+- The TCP stream is plain text: fine on a home network, not across the internet.
+- `+debug` versions compare equal to their release counterparts, so moving between the two is never refused as a downgrade.

docs/adr/0005-safe-mode-crash-reports-watchdog.md

@@ -0,0 +1,13 @@
+# Safe Mode, crash reports and a watched main loop, in every build
+
+Rollback protects against new firmware that fails Probation. It does nothing for firmware that was confirmed and crashes later: a corrupt setting, a server that sends something unexpected, a bug that takes an hour to show. Without a cable, such a device would restart forever. Three measures, in release and Debug Builds alike, keep it reachable:
+
+- **Safe Mode.** The firmware counts starts that follow a crash (panic or watchdog) in NVS, first thing at boot. After 3 in a row, it starts only the clock, Wi-Fi, the Update Service and, in a Debug Build, the Debug Console: no Apps, no IRC, no SD card, and a screen that says so with the address to push an update to. Any normal restart (a `reboot`, an update), or a minute of uptime, resets the count.
+- **Crash reports.** The same boot record keeps which version was running, so after a crash the firmware knows which one crashed, even when a Rollback has switched slots since. ESP-IDF already writes a core dump to its flash partition on a panic; after the restart the firmware prints its summary (task, PC, reason, backtrace) and raises a Notification. The `crash` command shows it again later. In a Debug Build, `scripts/rdbg.py crash` decodes the backtrace and `scripts/rdbg.py coredump` fetches the whole dump for `esp-coredump`, against the ELF of that exact build (`.pio/elves/`, named by version and ELF digest).
+- **The main loop is watched.** Arduino-ESP32 subscribes only core 0's idle task to the task watchdog, and the main loop runs on core 1: a stuck loop used to hang the device for good, with the screen frozen and the Debug Console unable to run commands. `enableLoopWDT()` makes a loop stuck for 5 s a panic, with a core dump, counted towards Safe Mode. And an installed update no longer depends on the main loop: the Update Service restarts into it by itself after 90 s.
+
+## Consequences
+
+- Nothing in the main loop may block for 5 s. Network and card work already run on their own tasks.
+- Safe Mode can't help when Wi-Fi or the Update Service itself is what crashes; that still needs USB.
+- Three crashes within a minute of each restart are needed to reach Safe Mode, so a crash loop costs about half a minute before the device becomes reachable.

docs/adr/0006-framework-rebuilt-for-smaller-tls-buffers.md

@@ -0,0 +1,19 @@
+# The framework is rebuilt with our own SDK settings, for smaller TLS buffers
+
+Arduino-ESP32 ships its ESP-IDF libraries prebuilt, with one `sdkconfig` for every ESP32-S3 board. Its TLS settings give every connection a 16 KB receive buffer and a 16 KB send buffer for its whole life. On a device with no PSRAM and about 340 KB of RAM, an IRC connection over TLS left a 12.6 KB low in M2, against a 40 KB floor.
+
+Those settings are compiled into the libraries, so changing them means rebuilding them. pioarduino supports this as a "hybrid compile": `custom_sdkconfig` in `platformio.ini` lists the settings, and the build regenerates the framework's libraries from ESP-IDF (the same 5.5.5 the prebuilt ones come from) before building the app. We set:
+
+- `MBEDTLS_ASYMMETRIC_CONTENT_LEN`, with 16 KB to receive (servers send full TLS records) and **4 KB to send** (IRC lines are short): 12 KB less per connection.
+- `MBEDTLS_DYNAMIC_BUFFER`, `DYNAMIC_FREE_CONFIG_DATA`, `DYNAMIC_FREE_CA_CERT`: buffers allocated when needed, and handshake-only data (the CA chain) freed once connected.
+
+The rebuild also follows the board definition instead of the generic one: PSRAM support is off (the Cardputer ADV has none) and the flash size is 8 MB.
+
+## Consequences
+
+- With IRC connected over TLS, a Debug Build has 78 KB free and a 59 KB low (it was 31 KB and 12.6 KB), and 46 KB at the lowest under the heaviest combined load measured (IRC, two refused installs, a 1.6 MB put and get).
+- The first build after a fresh checkout, or after changing `custom_sdkconfig`, takes about 4 minutes instead of 45 s: it downloads ESP-IDF into the PlatformIO volume and compiles it. Later builds reuse it.
+- Everything the firmware depends on was checked in the regenerated `sdkconfig`: app rollback, core dumps to flash (ELF), the 5 s task watchdog, FreeRTOS run-time stats, the certificate bundle.
+- The project now owns its partition table (`default_8MB.csv`, identical to the framework's), which the hybrid build requires. Changing it would break updates over the air: the app slots must stay where they are.
+- Generated files (`sdkconfig.*`, `managed_components/`, `.dummy/`) are ignored by git.
+- A TLS server that sends records over 16 KB would still fail, as before; one that needs us to send records over 4 KB would now fail. Neither happens with IRC.

docs/milestones/G1.md

@@ -0,0 +1,61 @@
+# G1 — Gemini client
+
+**Status:** done, tagged v0.5.0. Every step was checked on the device; reading Saved Pages with Wi-Fi off was checked by hand (2026-10-05).
+
+**Goal:** browse Geminispace from the Cardputer: fetch and read gemtext over TLS, follow links, answer input prompts, keep bookmarks, and save pages to the SD card to read later, offline. A side milestone between M2 and M3, tagged v0.5.0 when done.
+
+Gemini (geminiprotocol.net): one request per TLS connection on port 1965, the request is the URL and CRLF, the response a `<status> <meta>` header line, then the body. Most capsules use self-signed certificates: trust on first use is the norm.
+
+## Decisions (design round 2026-10-05)
+
+| # | Decision |
+|---|---|
+| Q70 | A milestone of its own, **G1**, before M3: plan, tests first, measured on the device, tagged v0.5.0. |
+| Q71 | **TOFU:** the first certificate seen for a host is pinned (SHA-256, in NVS). If it changes, the page isn't shown; a dialog shows both fingerprints and asks whether to trust the new one. Self-signed or expired certificates are fine; only a change counts. |
+| Q72 | Responses: 1x input (11 hidden, for passwords), 2x content, up to 5 redirects (3x), 4x/5x errors with the server's message. 6x (client certificates): "not supported". |
+| Q73 | `text/gemini` is rendered, other `text/*` shown as plain text. Anything else can be saved to `/gemini/downloads/`, not shown. |
+| Q74 | Up to **64 KB on screen**, larger pages truncated with a notice. Saving streams to the card, so a larger page is saved whole. |
+| Q75 | Gemtext rendering: text wrapped to the 40-column screen; `#`/`##`/`###` headings in bold and accent; `*` lists with bullets; `>` quotes indented and muted; preformatted blocks unwrapped, Left/Right to scroll; `=>` links with their label, numbered. |
+| Q76 | Up/Down scroll; Tab and Shift+Tab move between links; Enter follows; Backspace goes back; `g` opens the address line. Links to other protocols show their URL and aren't followed. |
+| Q77 | Back history of 20 URLs in RAM, with scroll positions; going back refetches (or reopens a Saved Page). **Bookmarks** in `/gemini/bookmarks.gmi` (a gemtext page, shown on the start page); `b` adds the current page. Without a card, a built-in start page. |
+| Q78 | Start page: bookmarks, then Saved Pages, then defaults: geminiprotocol.net, a search engine (kennedy.gemi.dev), an aggregator (Cosmos; Antenna was down when measured). |
+| Q79 | UTF-8 decoded; characters outside the Latin-1 fonts shown as `?`. |
+| Q80 | IRC and Gemini can run together: each fetch opens one connection, reads and closes it. If there isn't memory for a second TLS connection, the fetch fails with a clear message and IRC is untouched. Measured in step 1. |
+| Q81 | Debug aid: `gemini get <url>` prints the status, MIME type, size, certificate fingerprint and the first lines. URL resolution (RFC 3986), the response header and gemtext parsing are host-tested. |
+| Q82 | `s` saves the page on screen as a **Saved Page**: `/gemini/saved/<host>/<path>.gmi`, the gemtext as received plus a first line with its URL and save date. Saving again replaces it, and says so. |
+| Q83 | `S` saves the page and the pages it links to, one level deep: gemtext only, same host only, at most 30 pages, in the background with a progress Toast. |
+| Q84 | The start page lists Saved Pages, newest first, grouped by capsule; they open with no network. In a Saved Page, a link to another Saved Page opens the saved copy; other links fetch online if Wi-Fi is up, or say "not saved, offline". A Saved Page shows when it was saved; `r` refreshes it. |
+| Q86 | *Decided after step 1, revised after Q88.* **Two floors:** free heap stays above 40 KB in steady state; a fetch refuses to start below **55 KB** free ("not enough memory: stop IRC or retry"). The firmware's own allocations during a fetch (a page in RAM, a window) keep 20 KB free. With IRC connected, the TLS connection itself can briefly take the heap lower, depending on the server's record sizes: measured 24, 19.5, 15.5 and **13 KB**. *Accepted:* about 12 KB for a moment during a fetch with IRC up, rather than refusing most fetches (a 70 KB start floor) or dropping IRC's connection for each page. |
+| Q87 | *Decided in step 3.* **With a card, every page streams to `/gemini/cache/page.gmi`** in 1 KB pieces while its TLS connection is open; once the connection closes and its ~45 KB is back, the page is loaded into RAM as far as the 40 KB floor allows. The whole page stays on the card (Saved Pages copy it). Without a card, the page goes straight to RAM under the same two floors. Pages are held as lines in 4 KB chunks, never one large block (the largest free block with IRC connected is about 31 KB). |
+| Q88 | *Added after step 6.* **A page bigger than memory allows is read from the card as you scroll.** Opening it, one pass over its file counts the lines, records where every 64th starts (and whether it's inside a preformatted block), and loads the first window. Scrolling near either end of the window reads the next or previous one in the background, keeping the line on top of the screen where it is; the scrollbar follows the whole page. Display pages alternate between two cache files, so the one on screen is never overwritten by the next fetch; background jobs use a third. |
+| Q85 | Saved Pages are deleted from the App only (`d`, with confirmation), never by Storage Clean-up's age rules, like Notes. |
+
+## Measured (step 1)
+
+- `gemini://geminiprotocol.net/`: `20 text/gemini`, 1,184 bytes, TLS handshake 0.7–1.1 s, whole fetch 0.7–1.1 s; kennedy.gemi.dev 1.9 s. The fetch task's stack peaks at about 3.6 KB of 6.
+- **Heap, Debug Build, IRC connected over TLS:** about 68 KB free before a fetch. After the handshake the fetch holds about 32 KB (36–40 KB left); the handshake itself (certificate chain parsed with the 16 KB receive buffer allocated) dips to about **24 KB** for a second or two. Nothing leaks: the heap after matches the heap before.
+- **Step 3, Cosmos (31.6 KB) with IRC connected:** first stopped at 4.6 KB (RAM only, the transfer's 20 KB floor). Streamed to the card: the whole page on the card, 20 KB of it loaded, lowest free heap 19.5 KB during the transfer and 43 KB once loaded. Without IRC: the whole page in RAM. Redirects (Cosmos `31`), input (`10`), not found (`51`) and a changed certificate (refused, both fingerprints shown) all checked on the device.
+- **Steps 4–6 on the device:** Project Gemini and its relative links, Back with the scroll restored, a refused YouTube link; `b` bookmarks, `s` saves (and says when it replaced an older copy), `S` saved 6 of 6 pages, the start page lists both; a Saved Page opens from the card with its origin, its saved links open saved copies, `r` refreshes, `d` asks first; Kennedy's input prompt sent "cardputer" and got 87 results; emoji drawn as `?`.
+- **A bug found there:** refreshing first loaded the whole Saved Page into RAM just to read its origin, next to the App's copy and a TLS connection: the heap fell to 436 bytes. Now only the first line is read, and every fetch (pages, saves, refreshes) checks the 55 KB start floor. Lowest since boot afterwards: 53.8 KB.
+- **Windowed pages (Q88), Cosmos with IRC connected:** 226 of 419 lines in memory at first; paging down loaded lines 192–419 in one window, scrolling back up loaded 64 onwards, then 0 onwards. Window budgets count the memory the old window gives back.
+- **Heap during a fetch with IRC connected:** lowest 13–15.5 KB in later runs (24 and 19.5 KB earlier), the TLS receive buffers varying with the server's records. Accepted (Q86, revised).
+- Antenna (`warmedal.se`) doesn't answer, from the PC either; the default aggregator becomes Cosmos (`gemini://skyjake.fi/~Cosmos/`, which redirects to `cosmos.skyjake.fi`).
+
+## Done when
+
+- `gemini get gemini://geminiprotocol.net/` prints the header, size and fingerprint on the console.
+- The Gemini App opens the start page, follows links (relative ones included), goes back, and follows redirects.
+- An input prompt (e.g. a search) takes a query and shows the results.
+- A changed certificate stops the page and asks.
+- `s` saves a page, `S` a page and its links; with Wi-Fi off, Saved Pages open and their saved links work.
+- Bookmarks are added with `b` and listed on the start page.
+- With IRC connected over TLS, a fetch still works, and the free heap stays above 40 KB.
+
+## Work breakdown
+
+1. **Two TLS connections:** measure the heap with IRC connected while a Gemini fetch runs.
+2. **Parsers** (host-tested): URL parsing and relative resolution, the response header, gemtext lines.
+3. **Fetch** on its own task, with TOFU and `gemini get`.
+4. **Gemini App:** rendering, scrolling, links, history, the address line.
+5. **Input prompts, redirects, bookmarks, downloads.**
+6. **Saved Pages,** then saving with linked pages.

docs/milestones/M2.md

@@ -0,0 +1,59 @@
+# M2 — GNSS
+
+**Status:** done on the device (branch `m2`): every "Done when" item below is met.
+
+## Measured
+
+- **Cold start** (`$PCAS10,2`) to a 3D Fix, by a window: **73 s**, 5 satellites used of 8 in view. A restart of the ESP32 alone keeps the receiver's Fix (the Cap stays powered).
+- By a window: 3D Fix from GPS, GLONASS, Galileo and BeiDou, up to 14 of 17 satellites used, HDOP 1.0–1.3.
+- **Heap, Debug Build, GNSS on, IRC on TLS** (floor 40 KB; v0.2.1 had a 79 KB low):
+
+  | | Free | Lowest |
+  |---|---|---|
+  | Start of M2 | 31 KB | 12.6 KB |
+  | Stacks and buffers trimmed by measurement | 46 KB | 18 KB |
+  | mDNS removed | 54 KB | 34 KB |
+  | Framework rebuilt with smaller TLS buffers (ADR 0006) | **78 KB** | **59 KB** |
+
+  Under the heaviest combined load measured (IRC, two refused installs, a 1.6 MB put and get), the low is 46 KB. The cost had come mostly from the OTA and Debug Build work, not GNSS. Stacks were set to measured peak plus about 2 KB (loop 6 KB, update 5, storage 6, irc 6); after a TLS handshake the irc task has 1.7 KB left. IRC can now be stopped by hand (`/quit` in any state, `irc stop`), which frees its TLS memory.
+
+**Goal:** the device knows where it is and what time it is without a network: a GNSS Service in the background, a GNSS App with the position and a sky view of the satellites, the clock set from satellites when there's no NTP, and Tracks recorded to the SD card.
+
+**Hardware:** the Cap LoRa-1262 carries an ATGM336H-6N (AT6668), multi-constellation (GPS, BeiDou, Galileo, GLONASS, QZSS), with a ceramic antenna. NMEA over UART, 115200 8N1. **Measured (step 1, `gnss probe`): RX GPIO 15, TX GPIO 13, 115200 8N1**, as in Meshtastic's board file; M5Stack's page names GPIO 8 and 9, which are the internal I2C bus the keyboard controller sits on. Output is NMEA 4.10 style: `GN` RMC, VTG and GGA, one GSA per constellation with the system ID (1 GPS, 2 GLONASS, 3 Galileo, 4 BeiDou, 5 QZSS) in its last field, and a GSV sequence per constellation and signal (`GP`, `GL`, `GA`, …) with the signal ID last. RMC carries a time even without a Fix (status `V`), so only a Fix makes it trustworthy.
+
+## Decisions (design round 2026-10-04)
+
+| # | Decision |
+|---|---|
+| Q58 | Settings has a GNSS On/Off switch, **On by default**. Off puts the receiver in standby. *Measured:* `$PCAS12,<seconds>` (CASIC) stops its output within a second, for up to at least 65535 s, and any command wakes it within a second; Off sends `PCAS12,65535` (renewed hourly), On sends a hot start, `PCAS10,0`. |
+| Q59 | The **GNSS App** has two views, switched with Tab. *Position*: latitude, longitude, altitude, speed, course, Fix (none / 2D / 3D), satellites used and in view, HDOP, UTC time. *Sky*: the satellites placed by azimuth and elevation, coloured by constellation, filled when used in the Fix. |
+| Q60 | "Radar" in M2 means the Sky view. A radar of other Nodes by distance and bearing needs the mesh: M4. |
+| Q61 | The **Status Bar** shows a GNSS mark: absent when off, muted while searching, normal with a 2D Fix, with the satellite count with a 3D Fix. |
+| Q62 | GNSS time **sets the clock once there's a Fix**, and refreshes it every 10 minutes. *Revised in step 3:* the clock's trust order from M0 (Mesh < NTP < GNSS) already ranks GNSS above NTP, which is right: GNSS time is at least as accurate. So GNSS also corrects a clock NTP set, not only an unset one. |
+| Q63 | A **Track** is started and stopped in the GNSS App. It's written as GPX to `/gnss/tracks/<YYYYMMDD-HHMMSS>.gpx`, a point every 5 s when the position moved more than 5 m. It keeps recording with the App closed, with a Toast on start and stop and a Status Bar mark, and gets its own Storage Clean-up category. |
+| Q64 | Coordinates in **decimal degrees plus the Maidenhead locator**; a Settings switch for degrees, minutes and seconds. Metric units only. |
+| Q65 | **The position never leaves the device in M2.** Sharing it over the mesh, and at what precision, is decided in M4. |
+| Q66 | **Our own NMEA parser**, host-tested: RMC, GGA, GSA and GSV, with each talker ID mapped to its constellation. TinyGPSPlus (named in ADR 0001) doesn't track the satellite list across constellations, which the Sky view needs. |
+| Q67 | The receiver keeps its **defaults** (all constellations, 1 Hz). No receiver settings. Time to first fix is measured and recorded here. |
+| Q68 | Debug aids: `gnss status`, and `gnss nmea on/off` to stream the raw sentences to the console (USB serial and Debug Console). Raw NMEA is never written to the card. |
+
+**Lesson (step 3):** the first probe also tried the pins swapped, driving the receiver's output line from the ESP32 for about a second. The receiver then went silent until a full power cycle (an ESP32 restart doesn't cut the Cap's power). Never drive GPIO 15.
+
+## Done when
+
+- The GNSS Service reads NMEA in the background whatever App is on screen, and a 3D Fix appears outdoors.
+- The GNSS App shows the Position and Sky views, both live.
+- The Status Bar shows the GNSS mark per Q61.
+- With no Wi-Fi, the clock is set from GNSS after the first Fix.
+- A Track records while the App is closed, survives the screen turning off, and opens as valid GPX on the PC.
+- Settings → GNSS Off stops it (and the Status Bar mark goes away); On brings it back.
+- Free heap stays above about 40 KB with GNSS, Wi-Fi, IRC on TLS and the UI running.
+
+## Work breakdown
+
+1. **Hardware check:** a `gnss probe` command reads the candidate UART pins and reports which carries NMEA, at what baud rate, and which talker IDs. Then the standby command (Q58) and a first time to first fix.
+2. **NMEA parser** (host-tested): checksum, RMC, GGA, GSA, GSV across constellations, merged into one GNSS state (Fix, position, time, satellites).
+3. **GNSS Service:** UART on its own task, the parser, `gnss status` and `gnss nmea`, Settings On/Off.
+4. **Clock from GNSS** (Q62), and the Status Bar mark (Q61).
+5. **GNSS App:** Position view, Maidenhead and coordinate formats (host-tested), then the Sky view.
+6. **Tracks:** the 5 s / 5 m rule and GPX writing (host-tested), background recording, Clean-up category.

docs/milestones/OTA.md

@@ -0,0 +1,33 @@
+# OTA — Firmware Updates over Wi-Fi and from the SD card
+
+**Goal:** install new firmware without a USB cable. Push it from the PC over Wi-Fi, or drop it on the SD card. Unsigned images are refused, and a broken update rolls back by itself.
+
+## Decisions (design round 2026-10-03)
+
+| # | Decision |
+|---|---|
+| Q52 | Two sources: **push over Wi-Fi** from the PC, and **from the SD card**. Pulling from Gitea releases is deferred. |
+| Q53 | **Signed Update Files** (ECDSA P-256 over SHA-256). The private key stays in `~/.config/roro9stack/`, and the firmware embeds the public key (ADR 0003). |
+| Q54 | The device **always listens** for pushes on the LAN while Wi-Fi is Connected. *Revised in M2:* it was announced over mDNS as `roro9stack-<id>.local`; mDNS was removed to save RAM (it never crossed the dev box's routed network anyway). Pushes go to the IP shown in Settings → Firmware. |
+| Q55 | New firmware runs on **Probation**. It's confirmed once booted, UI drawn, Services started, 30 s without a crash, and Wi-Fi connected (if configured). Otherwise **Rollback**. A Toast reports either outcome. |
+| Q56 | **Downgrades are allowed**, with "older than the installed version" shown. |
+| Q57 | A valid push **installs right away**: progress screen, then reboot. The reboot waits for Text Entry to end, 60 s at most. |
+
+## Done when
+
+- `scripts/ota_keygen.sh` creates the key pair once. The public key is committed; the private key never is.
+- `scripts/flash.sh --ota` builds, signs and pushes to `roro9stack-<id>.local`. The device shows progress, reboots, and a Toast confirms the new version.
+- An Update File with a bad signature, a truncated or corrupted image, or no signature is refused, and the device keeps running.
+- Settings → About → **Update from SD** lists the `.ota` files in `/updates` and installs one.
+- A firmware that crashes during Probation rolls back to the previous version, and says so after the reboot.
+
+## Work breakdown
+
+1. **Update File format** (host-tested): header (magic, format, version, image size, SHA-256), signature, image. A streaming parser that hashes as it goes and decides accept / refuse / downgrade. The signature verifier sits behind an interface, so tests can inject one.
+2. **PC side:** key generation, `make_ota.py` (wraps `firmware.bin` into a signed `.ota`), and the push client. `flash.sh --ota` ties them together.
+3. **Device:** the Update Service.
+   - A listener on TCP 3232 plus mDNS.
+   - Writes the image to the inactive app slot, with the ECDSA check through mbedTLS.
+   - A progress screen, and a reboot that waits out Text Entry.
+4. **Probation and Rollback:** the health checks, confirming the image, and detecting a rollback after reboot to report it.
+5. **Update from SD:** the same parser, fed from the Storage Service's task (all card access stays there).

keys/ota-public.pem

@@ -0,0 +1,4 @@
+-----BEGIN PUBLIC KEY-----
+MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEIWzT07fvTpQxWjTdewMipYH6f42+
+mM8niHm+T8y+Mvjanb3H8hpYXg3VjuJGFtcHw/hFX0Q2f2AiSHMF0DhMbQ==
+-----END PUBLIC KEY-----

lib/apps_model/src/settings_menu.cpp

@@ -20,8 +20,10 @@ const RowDef kRows[] = {
     {Row::Region, Kind::Choice, "Region"},      {Row::Timezone, Kind::Choice, "Timezone"},
     {Row::Brightness, Kind::Slider, "Brightness"}, {Row::DimTimeout, Kind::Choice, "Dim after"},
     {Row::OffTimeout, Kind::Choice, "Screen off after"}, {Row::Sound, Kind::Toggle, "Sound & LED"},
+    {Row::Gnss, Kind::Toggle, "GNSS"}, {Row::Coordinates, Kind::Toggle, "Coordinates"},
     {Row::ProbeMacs, Kind::Toggle, "Probe MACs"}, {Row::Wifi, Kind::Page, "Wi-Fi"},
     {Row::Storage, Kind::Page, "Storage"},
+    {Row::Firmware, Kind::Page, "Firmware"},
     {Row::About, Kind::Page, "About"},
 };
 
@@ -78,6 +80,8 @@ std::string SettingsMenu::value(int i) const {
         case Row::DimTimeout: return formatSeconds(settings_.getInt(Setting::DimTimeoutS));
         case Row::OffTimeout: return formatSeconds(settings_.getInt(Setting::OffTimeoutS));
         case Row::Sound: return settings_.getBool(Setting::Sound) ? "On" : "Off";
+        case Row::Gnss: return settings_.getBool(Setting::GnssEnabled) ? "On" : "Off";
+        case Row::Coordinates: return settings_.getBool(Setting::CoordinatesDms) ? "Deg min sec" : "Decimal";
         case Row::ProbeMacs: return settings_.getBool(Setting::ProbeMacRaw) ? "Raw" : "Pseudonymised";
         case Row::Wifi: return settings_.getBool(Setting::WifiEnabled) ? "On" : "Off";
         default: return "";
@@ -121,6 +125,8 @@ std::string SettingsMenu::choose(int i, int c) {
 
 void SettingsMenu::toggle(int i) {
     if (row(i) == Row::Sound) settings_.setBool(Setting::Sound, !settings_.getBool(Setting::Sound));
+    if (row(i) == Row::Gnss) settings_.setBool(Setting::GnssEnabled, !settings_.getBool(Setting::GnssEnabled));
+    if (row(i) == Row::Coordinates) settings_.setBool(Setting::CoordinatesDms, !settings_.getBool(Setting::CoordinatesDms));
     if (row(i) == Row::ProbeMacs) settings_.setBool(Setting::ProbeMacRaw, !settings_.getBool(Setting::ProbeMacRaw));
 }
 

lib/apps_model/src/settings_menu.h

@@ -11,7 +11,7 @@ namespace roro {
 // values, choice lists and validation messages. Rendering and navigation live in the App.
 class SettingsMenu {
    public:
-    enum class Row { LongName, ShortName, Region, Timezone, Brightness, DimTimeout, OffTimeout, Sound, ProbeMacs, Wifi, Storage, About };
+    enum class Row { LongName, ShortName, Region, Timezone, Brightness, DimTimeout, OffTimeout, Sound, Gnss, Coordinates, ProbeMacs, Wifi, Storage, Firmware, About };
     enum class Kind { Text, Choice, Toggle, Slider, Page };
 
     explicit SettingsMenu(Settings& settings) : settings_(settings) {}

lib/gemini/src/gemini_response.cpp

@@ -0,0 +1,59 @@
+#include "gemini_response.h"
+
+#include <cctype>
+
+namespace roro::gemini {
+
+namespace {
+std::string trim(const std::string& s) {
+    size_t a = s.find_first_not_of(" \t"), b = s.find_last_not_of(" \t");
+    return a == std::string::npos ? "" : s.substr(a, b - a + 1);
+}
+std::string lower(std::string s) {
+    for (auto& c : s) c = static_cast<char>(std::tolower(static_cast<unsigned char>(c)));
+    return s;
+}
+}  // namespace
+
+bool parseHeader(const std::string& line, Header& out) {
+    if (line.size() < 2 || !std::isdigit(static_cast<unsigned char>(line[0])) ||
+        !std::isdigit(static_cast<unsigned char>(line[1])))
+        return false;
+    if (line.size() > 2 && line[2] != ' ') return false;
+    std::string meta = line.size() > 3 ? line.substr(3) : "";
+    if (meta.size() > 1024) return false;
+    out.status = (line[0] - '0') * 10 + (line[1] - '0');
+    out.meta = meta;
+    return true;
+}
+
+Category Header::category() const {
+    switch (status / 10) {
+        case 1: return Category::Input;
+        case 2: return Category::Success;
+        case 3: return Category::Redirect;
+        case 4: return Category::TemporaryFailure;
+        case 5: return Category::PermanentFailure;
+        case 6: return Category::ClientCertificate;
+        default: return Category::Unknown;
+    }
+}
+
+std::string Header::mimeType() const {
+    std::string type = lower(trim(meta.substr(0, meta.find(';'))));
+    return type.empty() ? "text/gemini" : type;
+}
+
+std::string Header::parameter(const std::string& name) const {
+    size_t pos = meta.find(';');
+    while (pos != std::string::npos) {
+        size_t next = meta.find(';', pos + 1);
+        std::string item = trim(meta.substr(pos + 1, next == std::string::npos ? std::string::npos : next - pos - 1));
+        size_t eq = item.find('=');
+        if (eq != std::string::npos && lower(trim(item.substr(0, eq))) == lower(name)) return trim(item.substr(eq + 1));
+        pos = next;
+    }
+    return "";
+}
+
+}  // namespace roro::gemini

lib/gemini/src/gemini_response.h

@@ -0,0 +1,23 @@
+#pragma once
+
+#include <string>
+
+namespace roro::gemini {
+
+enum class Category { Input, Success, Redirect, TemporaryFailure, PermanentFailure, ClientCertificate, Unknown };
+
+// The response header: "<two digits> <meta>", at most 1024 bytes of meta.
+struct Header {
+    int status = 0;
+    std::string meta;
+
+    Category category() const;
+    bool sensitiveInput() const { return status == 11; }
+    // 2x: the MIME type, lower-cased, without parameters ("text/gemini" when meta is empty).
+    std::string mimeType() const;
+    std::string parameter(const std::string& name) const;  // e.g. "charset"
+};
+
+bool parseHeader(const std::string& line, Header& out);
+
+}  // namespace roro::gemini

lib/gemini/src/gemini_url.cpp

@@ -0,0 +1,215 @@
+#include "gemini_url.h"
+
+#include <cctype>
+#include <cstdio>
+#include <cstdlib>
+#include <vector>
+
+#include "storage_paths.h"
+
+namespace roro::gemini {
+
+namespace {
+
+// RFC 3986, appendix B: ^(([^:/?#]+):)?(//([^/?#]*))?([^?#]*)(\?([^#]*))?(#(.*))?
+struct Parts {
+    std::string scheme, authority, path, query, fragment;
+    bool hasScheme = false, hasAuthority = false, hasQuery = false, hasFragment = false;
+};
+
+Parts split(const std::string& s) {
+    Parts p;
+    size_t i = 0;
+    size_t colon = s.find(':');
+    size_t stop = s.find_first_of("/?#");
+    if (colon != std::string::npos && colon > 0 && (stop == std::string::npos || colon < stop)) {
+        p.scheme = s.substr(0, colon);
+        p.hasScheme = true;
+        i = colon + 1;
+    }
+    if (s.compare(i, 2, "//") == 0) {
+        size_t end = s.find_first_of("/?#", i + 2);
+        if (end == std::string::npos) end = s.size();
+        p.authority = s.substr(i + 2, end - i - 2);
+        p.hasAuthority = true;
+        i = end;
+    }
+    size_t end = s.find_first_of("?#", i);
+    if (end == std::string::npos) end = s.size();
+    p.path = s.substr(i, end - i);
+    i = end;
+    if (i < s.size() && s[i] == '?') {
+        end = s.find('#', i);
+        if (end == std::string::npos) end = s.size();
+        p.query = s.substr(i + 1, end - i - 1);
+        p.hasQuery = true;
+        i = end;
+    }
+    if (i < s.size() && s[i] == '#') {
+        p.fragment = s.substr(i + 1);
+        p.hasFragment = true;
+    }
+    return p;
+}
+
+std::string lower(std::string s) {
+    for (auto& c : s) c = static_cast<char>(std::tolower(static_cast<unsigned char>(c)));
+    return s;
+}
+
+// RFC 3986, section 5.2.4.
+std::string removeDotSegments(std::string in) {
+    std::string out;
+    while (!in.empty()) {
+        if (in.compare(0, 3, "../") == 0) in.erase(0, 3);
+        else if (in.compare(0, 2, "./") == 0) in.erase(0, 2);
+        else if (in.compare(0, 3, "/./") == 0) in.replace(0, 3, "/");
+        else if (in == "/.") in = "/";
+        else if (in.compare(0, 4, "/../") == 0 || in == "/..") {
+            in = in == "/.." ? "/" : in.substr(3);
+            size_t slash = out.rfind('/');
+            out.erase(slash == std::string::npos ? 0 : slash);
+        } else if (in == "." || in == "..") in.clear();
+        else {
+            size_t next = in.find('/', in[0] == '/' ? 1 : 0);
+            if (next == std::string::npos) next = in.size();
+            out += in.substr(0, next);
+            in.erase(0, next);
+        }
+    }
+    return out;
+}
+
+// RFC 3986, section 5.2.3.
+std::string merge(const Parts& base, const std::string& refPath) {
+    if (base.hasAuthority && base.path.empty()) return "/" + refPath;
+    size_t slash = base.path.rfind('/');
+    return slash == std::string::npos ? refPath : base.path.substr(0, slash + 1) + refPath;
+}
+
+// RFC 3986, section 5.3.
+std::string recompose(const Parts& p) {
+    std::string out;
+    if (p.hasScheme) out += p.scheme + ":";
+    if (p.hasAuthority) out += "//" + p.authority;
+    out += p.path;
+    if (p.hasQuery) out += "?" + p.query;
+    if (p.hasFragment) out += "#" + p.fragment;
+    return out;
+}
+
+}  // namespace
+
+bool parseUrl(const std::string& text, Url& out) {
+    Parts p = split(text);
+    if (!p.hasScheme || !p.hasAuthority) return false;
+    out = Url();
+    out.scheme = lower(p.scheme);
+    out.authority = p.authority;
+    std::string hostPort = p.authority.substr(p.authority.find('@') == std::string::npos ? 0 : p.authority.find('@') + 1);
+    size_t colon = hostPort.rfind(':');
+    if (colon != std::string::npos && hostPort.find(']', colon) == std::string::npos) {
+        out.port = std::atoi(hostPort.c_str() + colon + 1);
+        hostPort = hostPort.substr(0, colon);
+    }
+    out.host = lower(hostPort);
+    if (out.host.empty()) return false;
+    out.path = p.path;
+    out.query = p.query;
+    out.fragment = p.fragment;
+    out.hasAuthority = true;
+    out.hasQuery = p.hasQuery;
+    out.hasFragment = p.hasFragment;
+    return true;
+}
+
+bool isGemini(const std::string& url) {
+    Parts p = split(url);
+    return p.hasScheme && lower(p.scheme) == "gemini";
+}
+
+std::string resolve(const std::string& baseText, const std::string& refText) {
+    Parts base = split(baseText), r = split(refText), t;
+    if (r.hasScheme) {
+        t = r;
+        t.path = removeDotSegments(r.path);
+    } else {
+        if (r.hasAuthority) {
+            t.authority = r.authority;
+            t.hasAuthority = true;
+            t.path = removeDotSegments(r.path);
+            t.query = r.query;
+            t.hasQuery = r.hasQuery;
+        } else {
+            if (r.path.empty()) {
+                t.path = base.path;
+                t.query = r.hasQuery ? r.query : base.query;
+                t.hasQuery = r.hasQuery || base.hasQuery;
+            } else {
+                t.path = removeDotSegments(r.path[0] == '/' ? r.path : merge(base, r.path));
+                t.query = r.query;
+                t.hasQuery = r.hasQuery;
+            }
+            t.authority = base.authority;
+            t.hasAuthority = base.hasAuthority;
+        }
+        t.scheme = base.scheme;
+        t.hasScheme = base.hasScheme;
+    }
+    t.fragment = r.fragment;
+    t.hasFragment = r.hasFragment;
+    return recompose(t);
+}
+
+std::string requestUrl(const std::string& url) {
+    Url u;
+    if (!parseUrl(url, u)) return url;
+    std::string out = u.scheme + "://" + u.host;
+    if (u.port > 0 && u.port != 1965) out += ":" + std::to_string(u.port);
+    out += u.path.empty() ? "/" : u.path;
+    if (u.hasQuery) out += "?" + u.query;
+    return out;
+}
+
+std::string encodeQuery(const std::string& text) {
+    std::string out;
+    for (unsigned char c : text) {
+        if (std::isalnum(c) || c == '-' || c == '_' || c == '.' || c == '~') out += static_cast<char>(c);
+        else {
+            char buf[4];
+            std::snprintf(buf, sizeof buf, "%%%02X", c);
+            out += buf;
+        }
+    }
+    return out;
+}
+
+std::string savedPath(const std::string& url) {
+    Url u;
+    if (!parseUrl(url, u)) return "/gemini/saved/unknown.gmi";
+    std::string out = "/gemini/saved/" + storage::sanitize(u.host + (u.port > 0 && u.port != 1965 ? "_" + std::to_string(u.port) : ""));
+    std::string path = u.path.empty() ? "/" : u.path;
+    std::vector<std::string> parts;
+    size_t start = 1;
+    while (start <= path.size()) {
+        size_t slash = path.find('/', start);
+        if (slash == std::string::npos) slash = path.size();
+        parts.push_back(path.substr(start, slash - start));
+        start = slash + 1;
+    }
+    if (parts.empty() || parts.back().empty()) {
+        if (!parts.empty()) parts.pop_back();
+        parts.push_back("index");
+    }
+    for (size_t i = 0; i < parts.size(); i++) {
+        std::string name = parts[i];
+        if (i + 1 == parts.size()) {
+            if (u.hasQuery) name += "~" + u.query;
+            if (name.size() < 4 || name.compare(name.size() - 4, 4, ".gmi") != 0) name += ".gmi";
+        }
+        out += "/" + storage::sanitize(name);
+    }
+    return out;
+}
+
+}  // namespace roro::gemini

lib/gemini/src/gemini_url.h

@@ -0,0 +1,28 @@
+#pragma once
+
+#include <string>
+
+namespace roro::gemini {
+
+// A URL split per RFC 3986 (appendix B). For Gemini, the host is lower-cased and the port
+// defaults to 1965.
+struct Url {
+    std::string scheme, authority, host, path, query, fragment;
+    int port = -1;
+    bool hasAuthority = false, hasQuery = false, hasFragment = false;
+    int portOrDefault() const { return port > 0 ? port : 1965; }
+};
+
+// False unless it has a scheme and a host: only absolute URLs are fetched.
+bool parseUrl(const std::string& text, Url& out);
+bool isGemini(const std::string& url);
+// `ref` against `base`, per RFC 3986 section 5.2 (dot segments included).
+std::string resolve(const std::string& base, const std::string& ref);
+// What goes on the wire: no fragment, lower-case host, never an empty path.
+std::string requestUrl(const std::string& url);
+// For input prompts: everything but unreserved characters percent-encoded (UTF-8 bytes).
+std::string encodeQuery(const std::string& text);
+// Where a Saved Page lives (Q82): /gemini/saved/<host>[_<port>]/<path>[~<query>].gmi
+std::string savedPath(const std::string& url);
+
+}  // namespace roro::gemini

lib/gemini/src/gemtext.cpp

@@ -0,0 +1,100 @@
+#include "gemtext.h"
+
+#include <cstdint>
+
+namespace roro::gemini {
+
+namespace {
+std::string trim(const std::string& s) {
+    size_t a = s.find_first_not_of(" \t"), b = s.find_last_not_of(" \t");
+    return a == std::string::npos ? "" : s.substr(a, b - a + 1);
+}
+}  // namespace
+
+GemLine parseGemLine(const std::string& line, bool& pre) {
+    GemLine g;
+    if (line.compare(0, 3, "```") == 0) {
+        g.type = LineType::PreToggle;
+        g.text = trim(line.substr(3));
+        pre = !pre;
+    } else if (pre) {
+        g.type = LineType::Preformatted;
+        g.text = line;
+    } else if (line.compare(0, 2, "=>") == 0) {
+        g.type = LineType::Link;
+        std::string rest = trim(line.substr(2));
+        size_t gap = rest.find_first_of(" \t");
+        g.url = rest.substr(0, gap);
+        g.text = gap == std::string::npos ? "" : trim(rest.substr(gap));
+        if (g.text.empty()) g.text = g.url;
+    } else if (line.compare(0, 3, "###") == 0) {
+        g.type = LineType::Heading3;
+        g.text = trim(line.substr(3));
+    } else if (line.compare(0, 2, "##") == 0) {
+        g.type = LineType::Heading2;
+        g.text = trim(line.substr(2));
+    } else if (line.compare(0, 1, "#") == 0) {
+        g.type = LineType::Heading1;
+        g.text = trim(line.substr(1));
+    } else if (line.compare(0, 2, "* ") == 0) {
+        g.type = LineType::ListItem;
+        g.text = trim(line.substr(2));
+    } else if (line.compare(0, 1, ">") == 0) {
+        g.type = LineType::Quote;
+        g.text = trim(line.substr(1));
+    } else {
+        g.text = line;
+    }
+    return g;
+}
+
+std::vector<GemLine> parseGemtext(const std::string& document) {
+    std::vector<GemLine> lines;
+    bool pre = false;
+    size_t start = 0;
+    while (start < document.size()) {
+        size_t end = document.find('\n', start);
+        if (end == std::string::npos) end = document.size();
+        std::string line = document.substr(start, end - start);
+        if (!line.empty() && line.back() == '\r') line.pop_back();
+        start = end + 1;
+        lines.push_back(parseGemLine(line, pre));
+    }
+    return lines;
+}
+
+std::string displayText(const std::string& s) {
+    std::string out;
+    size_t column = 0;
+    for (size_t i = 0; i < s.size();) {
+        unsigned char c = static_cast<unsigned char>(s[i]);
+        if (c == '\t') {
+            do out += ' ';
+            while (++column % 4);
+            i++;
+            continue;
+        }
+        if (c < 0x80) {
+            out += static_cast<char>(c);
+            i++;
+        } else {
+            int len = (c & 0xE0) == 0xC0 ? 2 : (c & 0xF0) == 0xE0 ? 3 : (c & 0xF8) == 0xF0 ? 4 : 0;
+            bool valid = len > 0 && i + len <= s.size();
+            for (int k = 1; valid && k < len; k++) valid = (static_cast<unsigned char>(s[i + k]) & 0xC0) == 0x80;
+            if (!valid) {
+                out += '?';
+                i++;
+            } else {
+                uint32_t cp = len == 2 ? (c & 0x1F) : len == 3 ? (c & 0x0F) : (c & 0x07);
+                for (int k = 1; k < len; k++) cp = (cp << 6) | (static_cast<unsigned char>(s[i + k]) & 0x3F);
+                if (cp <= 0xFF) out.append(s, i, len);  // Latin-1: the fonts have it
+                else out += '?';
+                i += len;
+            }
+        }
+        column++;
+    }
+    return out;
+}
+
+}  // namespace roro::gemini

lib/gemini/src/gemtext.h

@@ -0,0 +1,25 @@
+#pragma once
+
+#include <string>
+#include <vector>
+
+namespace roro::gemini {
+
+enum class LineType { Text, Link, Heading1, Heading2, Heading3, ListItem, Quote, PreToggle, Preformatted };
+
+// One gemtext line. Link: `url` and its label in `text` (the URL itself without a label).
+// PreToggle: the ``` line, with its alt text. Preformatted: kept exactly.
+struct GemLine {
+    LineType type = LineType::Text;
+    std::string text, url;
+};
+
+// One line; `preformatted` carries the ``` state from line to line (start with false).
+GemLine parseGemLine(const std::string& line, bool& preformatted);
+std::vector<GemLine> parseGemtext(const std::string& document);
+
+// For the Latin-1 fonts (Q79): valid UTF-8 up to U+00FF kept, anything else '?', and tabs
+// expanded to 4-column stops.
+std::string displayText(const std::string& utf8);
+
+}  // namespace roro::gemini

lib/gemini/src/text_buffer.cpp

@@ -0,0 +1,47 @@
+#include "text_buffer.h"
+
+#include <algorithm>
+
+namespace roro::gemini {
+
+void TextBuffer::append(const char* data, size_t len) {
+    bytes_ += len;
+    for (size_t i = 0; i < len; i++) {
+        if (data[i] == '\n') endLine();
+        else partial_ += data[i];
+    }
+}
+
+void TextBuffer::finish() {
+    if (!partial_.empty()) endLine();
+}
+
+void TextBuffer::endLine() {
+    if (!partial_.empty() && partial_.back() == '\r') partial_.pop_back();
+    size_t len = std::min<size_t>(partial_.size(), 0xFFFF);
+    // A line never spans two chunks: a new chunk when it doesn't fit (bigger if the line is).
+    if (chunks_.empty() || chunks_.back().size() + len > chunks_.back().capacity()) {
+        chunks_.emplace_back();
+        chunks_.back().reserve(std::max(kChunk, len));
+    }
+    std::string& chunk = chunks_.back();
+    lines_.push_back({static_cast<uint16_t>(chunks_.size() - 1), static_cast<uint16_t>(chunk.size()),
+                      static_cast<uint16_t>(len)});
+    chunk.append(partial_, 0, len);
+    partial_.clear();
+}
+
+std::string TextBuffer::line(size_t i) const {
+    if (i >= lines_.size()) return "";
+    const Ref& r = lines_[i];
+    return chunks_[r.chunk].substr(r.offset, r.length);
+}
+
+void TextBuffer::clear() {
+    chunks_.clear();
+    lines_.clear();
+    partial_.clear();
+    bytes_ = 0;
+}
+
+}  // namespace roro::gemini

lib/gemini/src/text_buffer.h

@@ -0,0 +1,38 @@
+#pragma once
+
+#include <cstddef>
+#include <cstdint>
+#include <string>
+#include <vector>
+
+namespace roro::gemini {
+
+// A page's text, kept as lines in 4 KB chunks: no large contiguous block (with IRC connected the
+// largest free block is about 31 KB) and no copy when it grows. About 4 bytes per line on top of
+// the text itself. Bytes are fed as they arrive; lines end at LF, a CR before it is dropped.
+class TextBuffer {
+   public:
+    static constexpr size_t kChunk = 4096;
+
+    void append(const char* data, size_t len);
+    void finish();  // the last line, if it has no line end
+    size_t lineCount() const { return lines_.size(); }
+    std::string line(size_t i) const;
+    size_t bytes() const { return bytes_; }
+    void clear();
+
+   private:
+    struct Ref {
+        uint16_t chunk;
+        uint16_t offset;
+        uint16_t length;
+    };
+    void endLine();
+
+    std::vector<std::string> chunks_;
+    std::vector<Ref> lines_;
+    std::string partial_;  // the line being received
+    size_t bytes_ = 0;
+};
+
+}  // namespace roro::gemini

lib/gnss/src/geo_format.cpp

@@ -0,0 +1,50 @@
+#include "geo_format.h"
+
+#include <cmath>
+#include <cstdio>
+
+namespace roro::gnss {
+
+namespace {
+const char* hemisphere(double degrees, bool latitude) {
+    return latitude ? (degrees < 0 ? "S" : "N") : (degrees < 0 ? "W" : "E");
+}
+}  // namespace
+
+std::string formatDecimal(double degrees, bool latitude) {
+    char buf[32];
+    std::snprintf(buf, sizeof buf, "%.5f\xC2\xB0 %s", std::fabs(degrees), hemisphere(degrees, latitude));
+    return buf;
+}
+
+std::string formatDms(double degrees, bool latitude) {
+    // Work in tenths of a second, so rounding carries into minutes and degrees.
+    long tenths = std::lround(std::fabs(degrees) * 36000.0);
+    long d = tenths / 36000, m = tenths / 600 % 60, s10 = tenths % 600;
+    char buf[40];
+    std::snprintf(buf, sizeof buf, "%ld\xC2\xB0 %02ld' %02ld.%ld\" %s", d, m, s10 / 10, s10 % 10,
+                  hemisphere(degrees, latitude));
+    return buf;
+}
+
+std::string maidenhead(double latitude, double longitude) {
+    double lon = std::fmin(std::fmax(longitude + 180.0, 0.0), 359.999999);
+    double lat = std::fmin(std::fmax(latitude + 90.0, 0.0), 179.999999);
+    std::string out;
+    out += static_cast<char>('A' + static_cast<int>(lon / 20));
+    out += static_cast<char>('A' + static_cast<int>(lat / 10));
+    out += static_cast<char>('0' + static_cast<int>(std::fmod(lon, 20) / 2));
+    out += static_cast<char>('0' + static_cast<int>(std::fmod(lat, 10)));
+    out += static_cast<char>('a' + static_cast<int>(std::fmod(lon, 2) * 12));
+    out += static_cast<char>('a' + static_cast<int>(std::fmod(lat, 1) * 24));
+    return out;
+}
+
+SkyPoint skyPosition(int azimuthDeg, int elevationDeg, int cx, int cy, int radius) {
+    int elevation = elevationDeg < 0 ? 0 : elevationDeg > 90 ? 90 : elevationDeg;
+    double r = radius * (90 - elevation) / 90.0;
+    double az = azimuthDeg * M_PI / 180.0;
+    return {cx + static_cast<int>(std::lround(r * std::sin(az))), cy - static_cast<int>(std::lround(r * std::cos(az)))};
+}
+
+}  // namespace roro::gnss

lib/gnss/src/geo_format.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include <string>
+
+namespace roro::gnss {
+
+// "50.86920° N": five decimals, about a metre.
+std::string formatDecimal(double degrees, bool latitude);
+// "50° 52' 09.1\" N" (Settings → Coordinates, Q64).
+std::string formatDms(double degrees, bool latitude);
+// The 6-character Maidenhead locator ("JO20ef"), as radio amateurs give their square.
+std::string maidenhead(double latitude, double longitude);
+
+// Where a satellite goes on the Sky view: the zenith in the centre, the horizon on the circle,
+// north up and east right (as seen looking at the sky from above, like a map).
+struct SkyPoint {
+    int x, y;
+};
+SkyPoint skyPosition(int azimuthDeg, int elevationDeg, int cx, int cy, int radius);
+
+}  // namespace roro::gnss

lib/gnss/src/nmea_parser.cpp

@@ -0,0 +1,234 @@
+#include "nmea_parser.h"
+
+#include <cstdlib>
+
+namespace roro::gnss {
+
+namespace {
+
+constexpr double kKmhPerKnot = 1.852;
+
+int hexValue(char c) {
+    if (c >= '0' && c <= '9') return c - '0';
+    if (c >= 'A' && c <= 'F') return c - 'A' + 10;
+    if (c >= 'a' && c <= 'f') return c - 'a' + 10;
+    return -1;
+}
+
+Constellation fromTalker(const std::string& t) {
+    if (t == "GP") return Constellation::Gps;
+    if (t == "GL") return Constellation::Glonass;
+    if (t == "GA") return Constellation::Galileo;
+    if (t == "GB" || t == "BD") return Constellation::BeiDou;
+    if (t == "GQ" || t == "QZ") return Constellation::Qzss;
+    if (t == "GI") return Constellation::Navic;
+    return Constellation::Unknown;  // GN: combined
+}
+
+// GSA's system ID field (NMEA 4.10).
+Constellation fromSystemId(int id) {
+    switch (id) {
+        case 1: return Constellation::Gps;
+        case 2: return Constellation::Glonass;
+        case 3: return Constellation::Galileo;
+        case 4: return Constellation::BeiDou;
+        case 5: return Constellation::Qzss;
+        case 6: return Constellation::Navic;
+        default: return Constellation::Unknown;
+    }
+}
+
+bool number(const std::string& s, double& out) {
+    if (s.empty()) return false;
+    char* end;
+    out = std::strtod(s.c_str(), &end);
+    return *end == '\0';
+}
+
+int integer(const std::string& s, int fallback = 0) {
+    double v;
+    return number(s, v) ? static_cast<int>(v) : fallback;
+}
+
+// "ddmm.mmmm" / "dddmm.mmmm" with its hemisphere letter.
+bool coordinate(const std::string& value, const std::string& hemisphere, double& out) {
+    double raw;
+    if (!number(value, raw) || hemisphere.empty()) return false;
+    int degrees = static_cast<int>(raw / 100);
+    out = degrees + (raw - degrees * 100) / 60.0;
+    if (hemisphere == "S" || hemisphere == "W") out = -out;
+    return true;
+}
+
+// Days since 1970-01-01 for a civil date (Howard Hinnant's algorithm).
+int64_t daysFromCivil(int y, int m, int d) {
+    y -= m <= 2;
+    const int64_t era = (y >= 0 ? y : y - 399) / 400;
+    const unsigned yoe = static_cast<unsigned>(y - era * 400);
+    const unsigned doy = (153 * (m + (m > 2 ? -3 : 9)) + 2) / 5 + d - 1;
+    const unsigned doe = yoe * 365 + yoe / 4 - yoe / 100 + doy;
+    return era * 146097 + static_cast<int64_t>(doe) - 719468;
+}
+
+}  // namespace
+
+const char* constellationName(Constellation c) {
+    switch (c) {
+        case Constellation::Gps: return "GPS";
+        case Constellation::Glonass: return "GLONASS";
+        case Constellation::Galileo: return "Galileo";
+        case Constellation::BeiDou: return "BeiDou";
+        case Constellation::Qzss: return "QZSS";
+        case Constellation::Navic: return "NavIC";
+        default: return "?";
+    }
+}
+
+int64_t GnssState::utcSeconds() const {
+    return daysFromCivil(year, month, day) * 86400 + hour * 3600 + minute * 60 + second;
+}
+
+void NmeaParser::feed(const char* data, size_t len) {
+    for (size_t i = 0; i < len; i++) {
+        char c = data[i];
+        if (c == '\n') {
+            if (!overflow_ && !line_.empty()) {
+                if (onLine) onLine(line_);
+                sentence(line_);
+            }
+            line_.clear();
+            overflow_ = false;
+        } else if (c != '\r') {
+            if (line_.size() >= kMaxLine) overflow_ = true;
+            else line_ += c;
+        }
+    }
+}
+
+bool NmeaParser::sentence(const std::string& line) {
+    size_t star = line.rfind('*');
+    if (line.size() < 7 || line[0] != '$' || star == std::string::npos || star + 3 != line.size()) {
+        bad_++;
+        return false;
+    }
+    uint8_t sum = 0;
+    for (size_t i = 1; i < star; i++) sum ^= static_cast<uint8_t>(line[i]);
+    int hi = hexValue(line[star + 1]), lo = hexValue(line[star + 2]);
+    if (hi < 0 || lo < 0 || sum != (hi << 4 | lo)) {
+        bad_++;
+        return false;
+    }
+    good_++;
+
+    Fields f;
+    size_t start = 1;
+    for (size_t i = 1; i <= star; i++)
+        if (i == star || line[i] == ',') {
+            f.push_back(line.substr(start, i - start));
+            start = i + 1;
+        }
+    if (f[0].size() < 5) return true;
+    std::string talker = f[0].substr(0, 2), type = f[0].substr(f[0].size() - 3);
+    if (type == "RMC") rmc(f);
+    else if (type == "GGA") gga(f);
+    else if (type == "GSA") gsa(f, fromTalker(talker));
+    else if (type == "GSV") gsv(f, fromTalker(talker));
+    return true;
+}
+
+void NmeaParser::rmc(const Fields& f) {
+    if (f.size() < 10) return;
+    bool active = f[2] == "A";
+    double lat, lon;
+    state_.positionValid = active && coordinate(f[3], f[4], lat) && coordinate(f[5], f[6], lon);
+    if (state_.positionValid) {
+        state_.latitude = lat;
+        state_.longitude = lon;
+    }
+    double knots, course;
+    state_.speedKmh = active && number(f[7], knots) ? static_cast<float>(knots * kKmhPerKnot) : 0;
+    state_.courseValid = active && number(f[8], course);
+    if (state_.courseValid) state_.courseDeg = static_cast<float>(course);
+
+    const std::string &t = f[1], &d = f[9];
+    state_.timeValid = active && t.size() >= 6 && d.size() == 6;
+    if (state_.timeValid) {
+        state_.hour = integer(t.substr(0, 2));
+        state_.minute = integer(t.substr(2, 2));
+        state_.second = integer(t.substr(4, 2));
+        state_.day = integer(d.substr(0, 2));
+        state_.month = integer(d.substr(2, 2));
+        state_.year = 2000 + integer(d.substr(4, 2));
+    }
+}
+
+void NmeaParser::gga(const Fields& f) {
+    if (f.size() < 10) return;
+    int quality = integer(f[6]);
+    double lat, lon, hdop, alt;
+    state_.positionValid = quality > 0 && coordinate(f[2], f[3], lat) && coordinate(f[4], f[5], lon);
+    if (state_.positionValid) {
+        state_.latitude = lat;
+        state_.longitude = lon;
+    }
+    state_.satellitesUsed = integer(f[7]);
+    if (number(f[8], hdop)) state_.hdop = static_cast<float>(hdop);
+    state_.altitudeValid = quality > 0 && number(f[9], alt);
+    if (state_.altitudeValid) state_.altitudeM = static_cast<float>(alt);
+}
+
+void NmeaParser::gsa(const Fields& f, Constellation talker) {
+    if (f.size() < 18) return;
+    int mode = integer(f[2], 1);
+    state_.fix = mode == 3 ? FixType::ThreeD : mode == 2 ? FixType::TwoD : FixType::None;
+    Constellation system = f.size() > 18 ? fromSystemId(integer(f[18])) : talker;
+    if (system == Constellation::Unknown) return;  // can't tell whose satellites these are
+    std::set<int>& used = used_[static_cast<int>(system)];
+    used.clear();
+    for (size_t i = 3; i <= 14; i++)
+        if (!f[i].empty()) used.insert(integer(f[i]));
+    rebuildSatellites();
+}
+
+void NmeaParser::gsv(const Fields& f, Constellation talker) {
+    if (f.size() < 4 || talker == Constellation::Unknown) return;
+    int total = integer(f[1]), number = integer(f[2]);
+    size_t extra = f.size() - 4;
+    int signal = extra % 4 == 1 ? integer(f.back()) : 0;  // NMEA 4.10 signal ID, last
+    auto key = std::make_pair(static_cast<int>(talker), signal);
+    std::vector<Satellite>& pending = pending_[key];
+    if (number == 1) pending.clear();
+    for (size_t i = 4; i + 3 < f.size(); i += 4) {
+        Satellite s;
+        s.system = talker;
+        s.prn = integer(f[i]);
+        s.elevation = integer(f[i + 1]);
+        s.azimuth = integer(f[i + 2]);
+        s.snr = integer(f[i + 3], -1);
+        if (s.prn > 0) pending.push_back(s);
+    }
+    if (number == total) {
+        inView_[key] = pending;
+        pending.clear();
+        rebuildSatellites();
+    }
+}
+
+void NmeaParser::rebuildSatellites() {
+    std::vector<Satellite> merged;
+    for (auto& [key, list] : inView_)
+        for (const Satellite& s : list) {
+            Satellite* same = nullptr;
+            for (auto& m : merged)
+                if (m.system == s.system && m.prn == s.prn) same = &m;
+            if (!same) merged.push_back(s);
+            else if (s.snr > same->snr) same->snr = s.snr;
+        }
+    for (auto& s : merged) {
+        auto it = used_.find(static_cast<int>(s.system));
+        s.used = it != used_.end() && it->second.count(s.prn) > 0;
+    }
+    state_.satellites = std::move(merged);
+}
+
+}  // namespace roro::gnss

lib/gnss/src/nmea_parser.h

@@ -0,0 +1,82 @@
+#pragma once
+
+#include <cstddef>
+#include <cstdint>
+#include <functional>
+#include <map>
+#include <set>
+#include <string>
+#include <utility>
+#include <vector>
+
+namespace roro::gnss {
+
+enum class Constellation : uint8_t { Unknown, Gps, Glonass, Galileo, BeiDou, Qzss, Navic };
+const char* constellationName(Constellation c);
+
+enum class FixType : uint8_t { None, TwoD, ThreeD };
+
+struct Satellite {
+    Constellation system = Constellation::Unknown;
+    int prn = 0;
+    int elevation = 0;  // degrees above the horizon
+    int azimuth = 0;    // degrees from north, clockwise
+    int snr = -1;       // dB-Hz; -1 when not tracked
+    bool used = false;  // part of the current Fix
+};
+
+// Everything the receiver has said, as of the last sentence (see CONTEXT.md: Fix).
+struct GnssState {
+    FixType fix = FixType::None;
+    bool positionValid = false;
+    double latitude = 0, longitude = 0;  // degrees, south and west negative
+    bool altitudeValid = false;
+    float altitudeM = 0;  // above mean sea level
+    float speedKmh = 0;
+    bool courseValid = false;
+    float courseDeg = 0;
+    int satellitesUsed = 0;
+    float hdop = 99.9f;
+    // UTC, trusted only with a Fix: the receiver reports a time without one, from its own clock.
+    bool timeValid = false;
+    int year = 0, month = 0, day = 0, hour = 0, minute = 0, second = 0;
+    std::vector<Satellite> satellites;  // in view, all constellations, one entry per satellite
+
+    int64_t utcSeconds() const;  // seconds since 1970-01-01 UTC; meaningful when timeValid
+};
+
+// NMEA 0183 (4.10 style, as the Cap's AT6668 sends it): RMC, GGA, GSA and GSV, with the
+// constellation taken from the talker ID or GSA's system ID field. Host-tested; no hardware here.
+class NmeaParser {
+   public:
+    // Raw bytes from the UART, in any chunks.
+    void feed(const char* data, size_t len);
+    // One sentence without its line end. False if malformed or its checksum is wrong.
+    bool sentence(const std::string& line);
+
+    // Called with every complete line fed in, valid or not (`gnss nmea on` echoes them).
+    std::function<void(const std::string&)> onLine;
+
+    const GnssState& state() const { return state_; }
+    uint32_t goodSentences() const { return good_; }
+    uint32_t badSentences() const { return bad_; }
+
+   private:
+    using Fields = std::vector<std::string>;
+    void rmc(const Fields& f);
+    void gga(const Fields& f);
+    void gsa(const Fields& f, Constellation talker);
+    void gsv(const Fields& f, Constellation talker);
+    void rebuildSatellites();
+
+    static constexpr size_t kMaxLine = 120;
+    std::string line_;
+    bool overflow_ = false;
+    uint32_t good_ = 0, bad_ = 0;
+    GnssState state_;
+    // GSV sequences per (constellation, signal): pending until their last message.
+    std::map<std::pair<int, int>, std::vector<Satellite>> pending_, inView_;
+    std::map<int, std::set<int>> used_;  // per constellation, from GSA
+};
+
+}  // namespace roro::gnss

lib/gnss/src/track.cpp

@@ -0,0 +1,76 @@
+#include "track.h"
+
+#include <cmath>
+#include <cstdio>
+#include <ctime>
+
+namespace roro::gnss {
+
+namespace {
+
+constexpr double kEarthRadiusM = 6371000.0;
+
+double radians(double degrees) { return degrees * M_PI / 180.0; }
+
+// UTC fields from seconds since 1970 (gmtime_r works on the device and the PC alike).
+struct tm utc(int64_t seconds) {
+    time_t t = static_cast<time_t>(seconds);
+    struct tm out;
+    gmtime_r(&t, &out);
+    return out;
+}
+
+}  // namespace
+
+double distanceMeters(double lat1, double lon1, double lat2, double lon2) {
+    double dLat = radians(lat2 - lat1), dLon = radians(lon2 - lon1);
+    double h = std::sin(dLat / 2) * std::sin(dLat / 2) +
+               std::cos(radians(lat1)) * std::cos(radians(lat2)) * std::sin(dLon / 2) * std::sin(dLon / 2);
+    return 2 * kEarthRadiusM * std::asin(std::sqrt(h));
+}
+
+bool TrackRule::due(uint32_t nowMs, double lat, double lon) {
+    if (any_ && (nowMs - lastMs_ < kEveryMs || distanceMeters(lat_, lon_, lat, lon) < kMinMeters)) return false;
+    any_ = true;
+    lastMs_ = nowMs;
+    lat_ = lat;
+    lon_ = lon;
+    return true;
+}
+
+std::string trackPath(int64_t utcSeconds) {
+    struct tm t = utc(utcSeconds);
+    char buf[48];
+    std::snprintf(buf, sizeof buf, "/gnss/tracks/%04d%02d%02d-%02d%02d%02d.gpx", t.tm_year + 1900, t.tm_mon + 1,
+                  t.tm_mday, t.tm_hour, t.tm_min, t.tm_sec);
+    return buf;
+}
+
+namespace gpx {
+
+std::string header(const std::string& name) {
+    return "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
+           "<gpx version=\"1.1\" creator=\"roro9stack\" xmlns=\"http://www.topografix.com/GPX/1/1\">\n"
+           "<trk><name>" + name + "</name><trkseg>";
+}
+
+std::string point(double lat, double lon, bool hasElevation, float elevationM, int64_t utcSeconds) {
+    struct tm t = utc(utcSeconds);
+    char buf[160], ele[32] = "";
+    if (hasElevation) std::snprintf(ele, sizeof ele, "<ele>%.1f</ele>", elevationM);
+    std::snprintf(buf, sizeof buf,
+                  "<trkpt lat=\"%.7f\" lon=\"%.7f\">%s<time>%04d-%02d-%02dT%02d:%02d:%02dZ</time></trkpt>", lat, lon,
+                  ele, t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, t.tm_hour, t.tm_min, t.tm_sec);
+    return buf;
+}
+
+std::string footer() { return "</trkseg></trk></gpx>"; }
+
+bool finished(const std::string& tail) {
+    size_t end = tail.find_last_not_of(" \r\n\t");
+    return end != std::string::npos && end + 1 >= 6 && tail.compare(end + 1 - 6, 6, "</gpx>") == 0;
+}
+
+}  // namespace gpx
+
+}  // namespace roro::gnss

lib/gnss/src/track.h

@@ -0,0 +1,40 @@
+#pragma once
+
+#include <cstdint>
+#include <string>
+
+namespace roro::gnss {
+
+// Great-circle distance in metres (haversine, mean Earth radius).
+double distanceMeters(double lat1, double lon1, double lat2, double lon2);
+
+// When a Track takes its next point (Q63): the first one always, then at least every 5 s and only
+// after moving at least 5 m, so standing still doesn't fill the card.
+class TrackRule {
+   public:
+    static constexpr uint32_t kEveryMs = 5000;
+    static constexpr double kMinMeters = 5.0;
+
+    // True if this position should be recorded (and is then remembered as the last point).
+    bool due(uint32_t nowMs, double lat, double lon);
+    void reset() { any_ = false; }
+
+   private:
+    bool any_ = false;
+    uint32_t lastMs_ = 0;
+    double lat_ = 0, lon_ = 0;
+};
+
+// "/gnss/tracks/YYYYMMDD-HHMMSS.gpx", from the UTC start time (Storage Clean-up reads its date).
+std::string trackPath(int64_t utcSeconds);
+
+// GPX 1.1, written a line at a time: the header when a Track starts, a point per line, the footer
+// when it stops. A file whose footer never came (power lost) is closed at the next boot.
+namespace gpx {
+std::string header(const std::string& name);
+std::string point(double lat, double lon, bool hasElevation, float elevationM, int64_t utcSeconds);
+std::string footer();
+bool finished(const std::string& tail);  // the end of a file: does it close the GPX?
+}  // namespace gpx
+
+}  // namespace roro::gnss

lib/ota/src/file_receiver.cpp

@@ -0,0 +1,114 @@
+#include "file_receiver.h"
+
+#include <algorithm>
+#include <cstdlib>
+#include <cstring>
+
+namespace roro {
+
+namespace {
+
+int hexDigit(char c) {
+    if (c >= '0' && c <= '9') return c - '0';
+    if (c >= 'a' && c <= 'f') return c - 'a' + 10;
+    if (c >= 'A' && c <= 'F') return c - 'A' + 10;
+    return -1;
+}
+
+// Splits on spaces (no iostreams: they cost about 200 KB of flash on the device).
+std::vector<std::string> words(const std::string& s) {
+    std::vector<std::string> out;
+    size_t i = 0;
+    while (i < s.size()) {
+        if (s[i] == ' ') {
+            i++;
+            continue;
+        }
+        size_t end = s.find(' ', i);
+        if (end == std::string::npos) end = s.size();
+        out.push_back(s.substr(i, end - i));
+        i = end;
+    }
+    return out;
+}
+
+}  // namespace
+
+std::string FileReceiver::begin(const std::string& args, uint32_t nowMs) {
+    reset();
+    std::vector<std::string> w = words(args);
+    if (w.size() != 3) return "usage: sd put <path> <size> <sha256>";
+    const std::string &path = w[0], &size = w[1], &sha = w[2];
+    if (path.empty() || path[0] != '/' || path.size() > 128 || path.find("..") != std::string::npos)
+        return "the path must be absolute, without ..";
+    if (size.empty() || size.size() > 9 || size.find_first_not_of("0123456789") != std::string::npos)
+        return "bad size";
+    uint32_t bytes = static_cast<uint32_t>(std::strtoul(size.c_str(), nullptr, 10));
+    if (bytes == 0 || bytes > kMaxBytes) return "bad size";
+    if (sha.size() != 64) return "bad sha256";
+    for (size_t i = 0; i < 32; i++) {
+        int hi = hexDigit(sha[2 * i]), lo = hexDigit(sha[2 * i + 1]);
+        if (hi < 0 || lo < 0) return "bad sha256";
+        expected_[i] = static_cast<uint8_t>(hi << 4 | lo);
+    }
+    path_ = path;
+    size_ = bytes;
+    lastActivityMs_ = nowMs;
+    chunk_.reserve(kChunk);
+    state_ = State::Receiving;
+    return "";
+}
+
+size_t FileReceiver::wanted() const {
+    if (state_ != State::Receiving) return 0;
+    return std::min<size_t>(kChunk, size_ - received_) - chunk_.size();
+}
+
+size_t FileReceiver::feed(const uint8_t* data, size_t len, uint32_t nowMs) {
+    if (state_ != State::Receiving || len == 0) return 0;
+    size_t take = std::min(len, wanted());
+    chunk_.insert(chunk_.end(), data, data + take);
+    sha_.update(data, take);
+    lastActivityMs_ = nowMs;
+    if (wanted() > 0) return take;
+
+    if (received_ + chunk_.size() == size_) {
+        // The last chunk: refuse it before writing if the file arrived damaged.
+        uint8_t got[32];
+        sha_.finish(got);
+        if (std::memcmp(got, expected_, sizeof got) != 0) {
+            fail("checksum mismatch");
+            return take;
+        }
+    }
+    state_ = State::Writing;
+    return take;
+}
+
+void FileReceiver::chunkWritten(bool ok, uint32_t nowMs) {
+    if (state_ != State::Writing) return;
+    if (!ok) return fail("write failed");
+    received_ += static_cast<uint32_t>(chunk_.size());
+    chunk_.clear();
+    lastActivityMs_ = nowMs;
+    state_ = received_ == size_ ? State::Finishing : State::Receiving;
+}
+
+void FileReceiver::finished(bool ok) {
+    if (state_ != State::Finishing) return;
+    if (!ok) return fail("rename failed");
+    state_ = State::Done;
+}
+
+void FileReceiver::tick(uint32_t nowMs) {
+    if (state_ != State::Receiving && state_ != State::Writing && state_ != State::Finishing) return;
+    if (nowMs - lastActivityMs_ >= kTimeoutMs) fail(state_ == State::Receiving ? "timed out" : "card not writable");
+}
+
+void FileReceiver::fail(const char* why) {
+    error_ = why;
+    chunk_.clear();
+    state_ = State::Failed;
+}
+
+}  // namespace roro

lib/ota/src/file_receiver.h

@@ -0,0 +1,66 @@
+#pragma once
+
+#include <cstddef>
+#include <cstdint>
+#include <string>
+#include <vector>
+
+#include "sha256.h"
+
+namespace roro {
+
+// One file sent over the USB serial console (scripts/sd_put.py), to put an Update File on the SD
+// card without taking the card out. The sender writes `sd put <path> <size> <sha256>`, then the raw
+// bytes, one chunk at a time, and waits for each chunk to be written before sending the next: the
+// serial driver drops bytes once its receive buffer is full. The file lands as `<path>.part` and is
+// renamed to `<path>` only once every byte has arrived and the checksum matches.
+class FileReceiver {
+   public:
+    static constexpr size_t kChunk = 1024;           // must stay below the serial receive buffer
+    static constexpr uint32_t kTimeoutMs = 5000;     // silence, or a card job that never completes
+    static constexpr uint32_t kMaxBytes = 8u << 20;  // larger than any app partition
+
+    enum class State {
+        Idle,
+        Receiving,  // waiting for bytes of the current chunk
+        Writing,    // chunk() is complete: write it to partPath(), then call chunkWritten()
+        Finishing,  // everything written and checked: rename partPath() to path(), then finished()
+        Done,
+        Failed,     // error() says why; partPath() should be removed
+    };
+
+    // Parses "<path> <size> <sha256 hex>". Returns "" when the transfer starts, or what's wrong.
+    std::string begin(const std::string& args, uint32_t nowMs);
+    // Takes bytes for the current chunk; returns how many were used (none while a chunk waits).
+    size_t feed(const uint8_t* data, size_t len, uint32_t nowMs);
+    void chunkWritten(bool ok, uint32_t nowMs);
+    void finished(bool ok);
+    void tick(uint32_t nowMs);
+    void reset() { *this = FileReceiver(); }
+
+    State state() const { return state_; }
+    bool active() const { return state_ != State::Idle; }
+    // Bytes still missing from the current chunk: read no more than this from the serial port.
+    size_t wanted() const;
+    const std::vector<uint8_t>& chunk() const { return chunk_; }
+    const std::string& path() const { return path_; }
+    std::string partPath() const { return path_ + ".part"; }
+    uint32_t size() const { return size_; }
+    uint32_t received() const { return received_; }
+    const std::string& error() const { return error_; }
+
+   private:
+    void fail(const char* why);
+
+    State state_ = State::Idle;
+    std::string path_;
+    uint32_t size_ = 0;
+    uint32_t received_ = 0;  // bytes in chunks already written
+    uint8_t expected_[32] = {};
+    Sha256 sha_;
+    std::vector<uint8_t> chunk_;
+    uint32_t lastActivityMs_ = 0;
+    std::string error_;
+};
+
+}  // namespace roro

lib/ota/src/probation.h

@@ -0,0 +1,28 @@
+#pragma once
+
+#include <cstdint>
+
+namespace roro {
+
+// Decides when new firmware on Probation (see CONTEXT.md) has proven healthy, or has failed in a
+// way that would leave no means to push a fix (Wi-Fi configured but never connecting).
+class Probation {
+   public:
+    enum class Verdict { Wait, Confirm, RollBack };
+    static constexpr uint32_t kHealthyAfterMs = 30000;
+    static constexpr uint32_t kWifiDeadlineMs = 180000;
+
+    // Checked first thing at boot, before anything that could crash. `attemptsBefore` counts earlier
+    // boots of this image on Probation; a second start means the first one died before confirming.
+    // (A second line behind the bootloader's own rollback, which aborts an image still pending.)
+    static bool rollBackAtBoot(bool onProbation, int attemptsBefore) { return onProbation && attemptsBefore >= 1; }
+
+    static Verdict judge(uint32_t uptimeMs, bool firstFrameDrawn, bool wifiConfigured, bool wifiConnected) {
+        if (wifiConfigured && !wifiConnected && uptimeMs >= kWifiDeadlineMs) return Verdict::RollBack;
+        if (uptimeMs < kHealthyAfterMs || !firstFrameDrawn) return Verdict::Wait;
+        if (wifiConfigured && !wifiConnected) return Verdict::Wait;
+        return Verdict::Confirm;
+    }
+};
+
+}  // namespace roro

lib/ota/src/safe_mode.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include <cstdint>
+
+namespace roro {
+
+// Safe Mode (CONTEXT.md): after kCrashLimit starts in a row that ended in a crash, the firmware
+// starts only what it takes to be fixed over the air (Wi-Fi, Firmware Updates, the Debug Console).
+// Rollback covers new firmware; this covers firmware that was confirmed and crashes anyway.
+struct SafeMode {
+    static constexpr int kCrashLimit = 3;
+    static constexpr uint32_t kStableAfterMs = 60000;  // then the count starts over
+
+    // Called first thing at boot with the count so far; returns the new count.
+    static int countAtBoot(bool lastStartWasCrash, int crashesBefore) {
+        return lastStartWasCrash ? crashesBefore + 1 : 0;
+    }
+    static bool active(int crashes) { return crashes >= kCrashLimit; }
+};
+
+}  // namespace roro

lib/ota/src/sha256.cpp

@@ -0,0 +1,85 @@
+#include "sha256.h"
+
+#include <cstring>
+
+namespace roro {
+
+namespace {
+const uint32_t K[64] = {
+    0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
+    0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
+    0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
+    0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
+    0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
+    0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
+    0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
+    0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2};
+
+inline uint32_t rotr(uint32_t x, int n) { return (x >> n) | (x << (32 - n)); }
+}  // namespace
+
+Sha256::Sha256() {
+    const uint32_t init[8] = {0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a,
+                              0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19};
+    std::memcpy(h_, init, sizeof(h_));
+}
+
+void Sha256::block(const uint8_t* p) {
+    uint32_t w[64];
+    for (int i = 0; i < 16; i++)
+        w[i] = (uint32_t(p[4 * i]) << 24) | (uint32_t(p[4 * i + 1]) << 16) | (uint32_t(p[4 * i + 2]) << 8) | p[4 * i + 3];
+    for (int i = 16; i < 64; i++) {
+        uint32_t s0 = rotr(w[i - 15], 7) ^ rotr(w[i - 15], 18) ^ (w[i - 15] >> 3);
+        uint32_t s1 = rotr(w[i - 2], 17) ^ rotr(w[i - 2], 19) ^ (w[i - 2] >> 10);
+        w[i] = w[i - 16] + s0 + w[i - 7] + s1;
+    }
+    uint32_t a = h_[0], b = h_[1], c = h_[2], d = h_[3], e = h_[4], f = h_[5], g = h_[6], h = h_[7];
+    for (int i = 0; i < 64; i++) {
+        uint32_t t1 = h + (rotr(e, 6) ^ rotr(e, 11) ^ rotr(e, 25)) + ((e & f) ^ (~e & g)) + K[i] + w[i];
+        uint32_t t2 = (rotr(a, 2) ^ rotr(a, 13) ^ rotr(a, 22)) + ((a & b) ^ (a & c) ^ (b & c));
+        h = g;
+        g = f;
+        f = e;
+        e = d + t1;
+        d = c;
+        c = b;
+        b = a;
+        a = t1 + t2;
+    }
+    h_[0] += a; h_[1] += b; h_[2] += c; h_[3] += d;
+    h_[4] += e; h_[5] += f; h_[6] += g; h_[7] += h;
+}
+
+void Sha256::update(const uint8_t* data, size_t len) {
+    bits_ += static_cast<uint64_t>(len) * 8;
+    while (len > 0) {
+        size_t take = 64 - used_ < len ? 64 - used_ : len;
+        std::memcpy(buf_ + used_, data, take);
+        used_ += take;
+        data += take;
+        len -= take;
+        if (used_ == 64) {
+            block(buf_);
+            used_ = 0;
+        }
+    }
+}
+
+void Sha256::finish(uint8_t out[32]) {
+    uint64_t bits = bits_;
+    uint8_t pad = 0x80;
+    update(&pad, 1);
+    uint8_t zero = 0;
+    while (used_ != 56) update(&zero, 1);
+    uint8_t len[8];
+    for (int i = 0; i < 8; i++) len[i] = static_cast<uint8_t>(bits >> (56 - 8 * i));
+    update(len, 8);
+    for (int i = 0; i < 8; i++) {
+        out[4 * i] = h_[i] >> 24;
+        out[4 * i + 1] = h_[i] >> 16;
+        out[4 * i + 2] = h_[i] >> 8;
+        out[4 * i + 3] = h_[i];
+    }
+}
+
+}  // namespace roro

lib/ota/src/sha256.h

@@ -0,0 +1,30 @@
+#pragma once
+
+#include <cstddef>
+#include <cstdint>
+
+namespace roro {
+
+// Plain SHA-256 (FIPS 180-4), streaming. Small and dependency-free, so the same code runs in the
+// PC tests and on the device.
+class Sha256 {
+   public:
+    Sha256();
+    void update(const uint8_t* data, size_t len);
+    void finish(uint8_t out[32]);
+
+    static void hash(const uint8_t* data, size_t len, uint8_t out[32]) {
+        Sha256 s;
+        s.update(data, len);
+        s.finish(out);
+    }
+
+   private:
+    void block(const uint8_t* p);
+    uint32_t h_[8];
+    uint8_t buf_[64];
+    size_t used_ = 0;
+    uint64_t bits_ = 0;
+};
+
+}  // namespace roro

lib/ota/src/update_parser.cpp

@@ -0,0 +1,87 @@
+#include "update_parser.h"
+
+#include <cstring>
+
+#include "version_compare.h"
+
+namespace roro {
+
+namespace {
+uint16_t u16(const uint8_t* p) { return p[0] | (p[1] << 8); }
+uint32_t u32(const uint8_t* p) { return p[0] | (p[1] << 8) | (p[2] << 16) | (uint32_t(p[3]) << 24); }
+}  // namespace
+
+void UpdateParser::fail(const std::string& why) {
+    if (state_ == State::Image) sink_.abort();
+    state_ = State::Failed;
+    error_ = why;
+}
+
+void UpdateParser::parseHeader() {
+    const uint8_t* h = header_;
+    if (std::memcmp(h, update::kMagic, 8) != 0) return fail("not an update file");
+    if (u16(h + 8) != update::kFormat || u16(h + 10) != update::kHeaderSize) return fail("unsupported update format");
+    imageSize_ = u32(h + 12);
+    if (imageSize_ == 0 || imageSize_ > maxImage_) return fail("image doesn't fit the update slot");
+    std::memcpy(expectedHash_, h + 16, 32);
+    version_.assign(reinterpret_cast<const char*>(h + 48), strnlen(reinterpret_cast<const char*>(h + 48), 32));
+
+    size_t sigLen = u16(h + 80);
+    if (sigLen == 0 || sigLen > update::kMaxSignature) return fail("missing signature");
+    uint8_t digest[32];
+    Sha256::hash(h, update::kSignedBytes, digest);
+    if (!verifier_.verify(digest, h + 82, sigLen)) return fail("bad signature (wrong key)");
+
+    downgrade_ = versionOlder(version_, installed_);
+    if (!sink_.begin(imageSize_)) return fail("could not prepare the update slot");
+    state_ = State::Image;
+}
+
+void UpdateParser::feed(const uint8_t* data, size_t len) {
+    while (len > 0 && (state_ == State::Header || state_ == State::Image)) {
+        if (state_ == State::Header) {
+            size_t take = std::min(len, update::kHeaderSize - headerUsed_);
+            std::memcpy(header_ + headerUsed_, data, take);
+            headerUsed_ += take;
+            data += take;
+            len -= take;
+            if (headerUsed_ == update::kHeaderSize) parseHeader();
+        } else {
+            size_t take = std::min(len, imageSize_ - received_);
+            if (take == 0) return fail("data after the end of the image");
+            hash_.update(data, take);
+            if (!sink_.write(data, take)) return fail("writing the update failed");
+            received_ += take;
+            data += take;
+            len -= take;
+        }
+    }
+    if (len > 0 && state_ == State::Image) fail("data after the end of the image");
+}
+
+bool UpdateParser::end() {
+    if (state_ == State::Done) return true;
+    if (state_ != State::Image) {
+        if (state_ == State::Header) fail("update file too short");
+        return false;
+    }
+    if (received_ != imageSize_) {
+        fail("update file too short");
+        return false;
+    }
+    uint8_t got[32];
+    hash_.finish(got);
+    if (std::memcmp(got, expectedHash_, 32) != 0) {
+        fail("image corrupted (hash mismatch)");
+        return false;
+    }
+    if (!sink_.finish()) {
+        state_ = State::Failed;
+        error_ = "could not switch to the new image";
+        return false;
+    }
+    state_ = State::Done;
+    return true;
+}
+
+}  // namespace roro

lib/ota/src/update_parser.h

@@ -0,0 +1,82 @@
+#pragma once
+
+#include <cstddef>
+#include <cstdint>
+#include <string>
+
+#include "sha256.h"
+
+namespace roro {
+
+// The Update File (see CONTEXT.md): a 160-byte header, then the firmware image. All integers are
+// little-endian.
+//   0  magic "RORO-OTA"     8  u16 format (1)    10 u16 header size (160)   12 u32 image size
+//  16  image SHA-256[32]   48  version, NUL-padded [32]
+//  80  u16 signature length   82  signature (DER, up to 72 bytes)   154 reserved
+// The signature covers SHA-256 of bytes 0..79, which include the image's hash, so a bad signature
+// is caught before anything is written, and a bad image when its hash is checked at the end.
+namespace update {
+constexpr char kMagic[] = "RORO-OTA";
+constexpr uint16_t kFormat = 1;
+constexpr size_t kHeaderSize = 160;
+constexpr size_t kSignedBytes = 80;
+constexpr size_t kMaxSignature = 72;
+}  // namespace update
+
+class SignatureVerifier {
+   public:
+    virtual ~SignatureVerifier() = default;
+    virtual bool verify(const uint8_t digest[32], const uint8_t* signature, size_t len) = 0;
+};
+
+// Where the image goes (the inactive app slot on the device).
+class UpdateSink {
+   public:
+    virtual ~UpdateSink() = default;
+    virtual bool begin(size_t imageSize) = 0;
+    virtual bool write(const uint8_t* data, size_t len) = 0;
+    virtual bool finish() = 0;  // make it the image to boot next
+    virtual void abort() = 0;
+};
+
+// Streams an Update File into a sink: checks the header and signature first, then hashes the image
+// as it passes through, and only finishes the sink if everything matches.
+class UpdateParser {
+   public:
+    enum class State { Header, Image, Done, Failed };
+
+    UpdateParser(SignatureVerifier& verifier, UpdateSink& sink, size_t maxImageSize, std::string installedVersion)
+        : verifier_(verifier), sink_(sink), maxImage_(maxImageSize), installed_(std::move(installedVersion)) {}
+
+    void feed(const uint8_t* data, size_t len);
+    bool end();  // no more data: true if the update was installed
+    // The whole image the header announced has arrived (the sender need not close the connection).
+    bool complete() const { return state_ == State::Image && received_ == imageSize_; }
+
+    State state() const { return state_; }
+    const std::string& error() const { return error_; }
+    const std::string& version() const { return version_; }
+    bool isDowngrade() const { return downgrade_; }
+    int percent() const { return imageSize_ ? static_cast<int>(received_ * 100 / imageSize_) : 0; }
+
+   private:
+    void parseHeader();
+    void fail(const std::string& why);
+
+    SignatureVerifier& verifier_;
+    UpdateSink& sink_;
+    size_t maxImage_;
+    std::string installed_;
+
+    State state_ = State::Header;
+    uint8_t header_[update::kHeaderSize];
+    size_t headerUsed_ = 0;
+    uint8_t expectedHash_[32];
+    size_t imageSize_ = 0;
+    size_t received_ = 0;
+    Sha256 hash_;
+    std::string version_, error_;
+    bool downgrade_ = false;
+};
+
+}  // namespace roro

lib/ota/src/version_compare.h

@@ -0,0 +1,33 @@
+#pragma once
+
+#include <cstdlib>
+#include <string>
+
+namespace roro {
+
+// True if `a` is an older release than `b`, comparing "vMAJOR.MINOR.PATCH" and ignoring any
+// git-describe suffix ("-3-gabc1234-dirty"). Anything that doesn't parse is never called older.
+inline bool parseVersion(const std::string& s, int out[3]) {
+    size_t pos = s.size() > 0 && s[0] == 'v' ? 1 : 0;
+    for (int i = 0; i < 3; i++) {
+        if (pos >= s.size() || s[pos] < '0' || s[pos] > '9') return false;
+        char* end;
+        out[i] = static_cast<int>(std::strtol(s.c_str() + pos, &end, 10));
+        pos = end - s.c_str();
+        if (i < 2) {
+            if (pos >= s.size() || s[pos] != '.') return false;
+            pos++;
+        }
+    }
+    return true;
+}
+
+inline bool versionOlder(const std::string& a, const std::string& b) {
+    int x[3], y[3];
+    if (!parseVersion(a, x) || !parseVersion(b, y)) return false;
+    for (int i = 0; i < 3; i++)
+        if (x[i] != y[i]) return x[i] < y[i];
+    return false;
+}
+
+}  // namespace roro

lib/services/src/settings.cpp

@@ -29,6 +29,8 @@ const Definition kDefinitions[] = {
     {"sound", Kind::Bool, 1, nullptr, 0, 1},
     {"probe_mac_raw", Kind::Bool, 1, nullptr, 0, 1},
     {"wifi_on", Kind::Bool, 1, nullptr, 0, 1},
+    {"gnss_on", Kind::Bool, 1, nullptr, 0, 1},
+    {"coord_dms", Kind::Bool, 0, nullptr, 0, 1},
 };
 static_assert(sizeof(kDefinitions) / sizeof(kDefinitions[0]) == static_cast<size_t>(Setting::Count),
               "every Setting needs a definition");

lib/services/src/settings.h

@@ -21,6 +21,8 @@ enum class Setting : uint8_t {
     Sound,            // bool
     ProbeMacRaw,      // bool: probe-request Logs keep raw MAC addresses
     WifiEnabled,      // bool: the Wi-Fi Service stays Connected when a Saved Network is in range
+    GnssEnabled,      // bool: the GNSS Service reads the receiver (M2, Q58)
+    CoordinatesDms,   // bool: show degrees, minutes and seconds instead of decimal degrees (Q64)
     Count
 };
 

lib/storage_model/src/cleanup_plan.h

@@ -20,6 +20,7 @@ inline const CleanupCategory kCleanupCategories[] = {
     {"IRC logs", "/irc"},
     {"Wi-Fi scan logs", "/wifi/scans"},
     {"Wi-Fi captures", "/captures/wifi"},
+    {"GNSS tracks", "/gnss/tracks"},
 };
 
 enum class CleanupAge { OneMonth, ThreeMonths, SixMonths, OneYear, Everything };

platformio.ini

@@ -20,6 +20,25 @@ build_flags =
 lib_deps =
     m5stack/M5Cardputer @ 1.1.1
 test_ignore = *
+; Smaller TLS buffers (M2): the framework is rebuilt with these settings (pioarduino "hybrid
+; compile"). Receive stays 16 KB (servers send full TLS records); send drops to 4 KB (IRC lines are
+; short); buffers are allocated as needed and handshake-only data is freed once connected.
+custom_sdkconfig =
+    CONFIG_MBEDTLS_ASYMMETRIC_CONTENT_LEN=y
+    CONFIG_MBEDTLS_SSL_IN_CONTENT_LEN=16384
+    CONFIG_MBEDTLS_SSL_OUT_CONTENT_LEN=4096
+    CONFIG_MBEDTLS_DYNAMIC_BUFFER=y
+    CONFIG_MBEDTLS_DYNAMIC_FREE_CONFIG_DATA=y
+    CONFIG_MBEDTLS_DYNAMIC_FREE_CA_CERT=y
+
+; Debug Build: the same firmware plus the Debug Console on TCP 2323 (see ADR 0004). The token comes
+; from ~/.config/roro9stack/debug-token, passed in by scripts/_docker.sh; it's never committed.
+[env:cardputer-adv-debug]
+extends = env:cardputer-adv
+extra_scripts = pre:scripts/version.py, pre:scripts/debug_flags.py
+build_flags =
+    ${env:cardputer-adv.build_flags}
+    -DRORO_DEBUG
 
 ; Host-side unit tests for pure logic (no hardware).
 [env:native]

scripts/_docker.sh

@@ -4,9 +4,17 @@ ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
 
 docker build -q -t "$IMAGE" "$ROOT/docker" >/dev/null
 
+# The Debug Console token (ADR 0004): made once, kept with the OTA key, never committed.
+DEBUG_TOKEN_FILE="$HOME/.config/roro9stack/debug-token"
+if [ ! -s "$DEBUG_TOKEN_FILE" ]; then
+    mkdir -p "$(dirname "$DEBUG_TOKEN_FILE")"
+    (umask 077 && od -An -tx1 -N16 /dev/urandom | tr -d ' \n' > "$DEBUG_TOKEN_FILE")
+fi
+
 run_in_container() {
     docker run --rm \
         -u "$(id -u):$(id -g)" -e HOME=/tmp \
+        -e RORO_DEBUG_TOKEN="$(cat "$DEBUG_TOKEN_FILE")" \
         -v "$ROOT:/work" \
         -v roro9stack-pio:/pio \
         "${DOCKER_EXTRA[@]}" \

scripts/ci.sh

@@ -4,4 +4,4 @@ set -euo pipefail
 source "$(dirname "$0")/_docker.sh"
 DOCKER_EXTRA=()
 
-run_in_container bash -c 'git config --global --add safe.directory /work && pio test -e native && pio run -e cardputer-adv'
+run_in_container bash -c 'git config --global --add safe.directory /work && pio test -e native && pio run -e cardputer-adv -e cardputer-adv-debug'

scripts/debug_flags.py

@@ -0,0 +1,12 @@
+# Debug Builds only: compiles in the Debug Console token from $RORO_DEBUG_TOKEN (set by _docker.sh
+# from ~/.config/roro9stack/debug-token). Refuses to build without one rather than use a default.
+import os
+import re
+import sys
+
+Import("env")  # noqa: F821  (provided by PlatformIO)
+
+token = os.environ.get("RORO_DEBUG_TOKEN", "").strip()
+if not re.fullmatch(r"[0-9a-f]{32}", token):
+    sys.exit("debug build: RORO_DEBUG_TOKEN is missing; build through scripts/ci.sh or scripts/flash.sh --debug")
+env.Append(CPPDEFINES=[("RORO_DEBUG_TOKEN", '\\"%s\\"' % token)])  # noqa: F821

scripts/decode_backtrace.sh

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+# Turns crash addresses into functions and source lines, using the archived ELF of the build that
+# crashed (.pio/elves/, kept by scripts/version.py).
+# Usage: scripts/decode_backtrace.sh <version or ELF sha256 prefix> <address>...
+set -euo pipefail
+source "$(dirname "$0")/_docker.sh"
+[ $# -ge 2 ] || { echo "Usage: scripts/decode_backtrace.sh <version|sha> <address>..." >&2; exit 1; }
+ELF="$(ls -t "$ROOT"/.pio/elves/*"$1"*.elf 2>/dev/null | head -1 || true)"
+[ -n "$ELF" ] || { echo "No archived ELF matches '$1' in .pio/elves/" >&2; exit 1; }
+echo "using ${ELF#$ROOT/}" >&2
+DOCKER_EXTRA=()
+run_in_container /pio/tools/toolchain-xtensa-esp-elf/bin/xtensa-esp32s3-elf-addr2line -pfiaC -e "/work/${ELF#$ROOT/}" "${@:2}"

scripts/decode_coredump.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+# Full post-mortem of a core dump fetched with `scripts/rdbg.py coredump`: every task's backtrace,
+# registers and the crashed task's stack, via esp-coredump and GDB in the container.
+# Usage: scripts/decode_coredump.sh <core.bin> <version or ELF sha256 prefix>
+set -euo pipefail
+source "$(dirname "$0")/_docker.sh"
+[ $# -eq 2 ] || { echo "Usage: scripts/decode_coredump.sh <core.bin> <version|sha>" >&2; exit 1; }
+CORE="$(realpath "$1")"
+ELF="$(ls -t "$ROOT"/.pio/elves/*"$2"*.elf 2>/dev/null | head -1 || true)"
+[ -n "$ELF" ] || { echo "No archived ELF matches '$2' in .pio/elves/" >&2; exit 1; }
+echo "using ${ELF#$ROOT/}" >&2
+DOCKER_EXTRA=(-v "$(dirname "$CORE"):/core:ro")
+run_in_container /pio/penv/bin/esp-coredump --chip esp32s3 info_corefile -t raw \
+    -g /pio/tools/tool-xtensa-esp-elf-gdb/bin/xtensa-esp32s3-elf-gdb \
+    -c "/core/$(basename "$CORE")" "/work/${ELF#$ROOT/}"

scripts/flash.sh

@@ -1,11 +1,33 @@
 #!/usr/bin/env bash
 # Flash the firmware over USB, then open the serial monitor.
-# Usage: scripts/flash.sh [port]   (default: the first Espressif device found)
+# Usage: scripts/flash.sh [--debug] [port]        USB (default: the first Espressif device found)
+#        scripts/flash.sh [--debug] --ota [host]  Wi-Fi: build, sign and push a Firmware Update
+#                                                 (host: the device's IP from Settings > About, or $RORO_OTA_HOST)
+# --debug builds the Debug Build (cardputer-adv-debug): the Debug Console on TCP 2323, see ADR 0004.
 set -euo pipefail
+ENV=cardputer-adv
+if [ "${1:-}" = "--debug" ]; then
+    ENV=cardputer-adv-debug
+    shift
+fi
+
+if [ "${1:-}" = "--ota" ]; then
+    ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+    HOST="${2:-${RORO_OTA_HOST:-}}"
+    [ -n "$HOST" ] || { echo "Usage: scripts/flash.sh --ota <device IP> (or set RORO_OTA_HOST)" >&2; exit 1; }
+    source "$(dirname "$0")/_docker.sh"
+    DOCKER_EXTRA=()
+    run_in_container bash -c "git config --global --add safe.directory /work && pio run -e $ENV" | tail -3
+    VERSION="$(git -C "$ROOT" describe --tags --always --dirty)"
+    [ "$ENV" = cardputer-adv-debug ] && VERSION="$VERSION+debug"  # as scripts/version.py names it
+    OUT="$ROOT/.pio/build/$ENV/roro9stack-$VERSION.ota"
+    "$ROOT/scripts/make_ota.py" "$ROOT/.pio/build/$ENV/firmware.bin" "$VERSION" "$OUT"
+    exec "$ROOT/scripts/ota_push.py" "$OUT" "$HOST"
+fi
 PORT="${1:-$(readlink -f /dev/serial/by-id/*Espressif* 2>/dev/null | head -1)}"
 [ -n "$PORT" ] || { echo "No Cardputer found on USB (is it plugged in / attached to the VM?)" >&2; exit 1; }
 source "$(dirname "$0")/_docker.sh"
 docker rm -f roro9stack-serial >/dev/null 2>&1 || true  # a serial log would hold the port
 DOCKER_EXTRA=(--device "$PORT" --group-add "$(stat -c %g "$PORT")" -it)
 
-run_in_container bash -c "git config --global --add safe.directory /work && pio run -e cardputer-adv -t upload --upload-port $PORT && pio device monitor -p $PORT -b 115200"
+run_in_container bash -c "git config --global --add safe.directory /work && pio run -e $ENV -t upload --upload-port $PORT && pio device monitor -p $PORT -b 115200"

scripts/make_ota.py

@@ -0,0 +1,50 @@
+#!/usr/bin/env python3
+"""Wraps a firmware image into a signed Update File (.ota). See lib/ota/src/update_parser.h.
+
+Usage: scripts/make_ota.py <firmware.bin> <version> <out.ota> [private key]
+Signs with openssl (ECDSA P-256 over SHA-256 of the header's first 80 bytes).
+"""
+import hashlib
+import os
+import struct
+import subprocess
+import sys
+import tempfile
+
+HEADER_SIZE = 160
+SIGNED_BYTES = 80
+MAX_SIGNATURE = 72
+
+
+def main():
+    if len(sys.argv) < 4:
+        sys.exit(__doc__)
+    image_path, version, out_path = sys.argv[1:4]
+    key = sys.argv[4] if len(sys.argv) > 4 else os.environ.get(
+        "RORO_OTA_KEY", os.path.expanduser("~/.config/roro9stack/ota-key.pem"))
+    if not os.path.exists(key):
+        sys.exit(f"No signing key at {key}: run scripts/ota_keygen.sh first.")
+
+    image = open(image_path, "rb").read()
+    version_bytes = version.encode()[:31]
+    signed = (b"RORO-OTA" + struct.pack("<HHI", 1, HEADER_SIZE, len(image)) +
+              hashlib.sha256(image).digest() + version_bytes.ljust(32, b"\0"))
+    assert len(signed) == SIGNED_BYTES
+
+    with tempfile.NamedTemporaryFile() as f:
+        f.write(signed)
+        f.flush()
+        signature = subprocess.run(["openssl", "dgst", "-sha256", "-sign", key, f.name],
+                                   check=True, capture_output=True).stdout
+    if len(signature) > MAX_SIGNATURE:
+        sys.exit("unexpected signature size")
+
+    header = signed + struct.pack("<H", len(signature)) + signature
+    header = header.ljust(HEADER_SIZE, b"\0")
+    with open(out_path, "wb") as out:
+        out.write(header + image)
+    print(f"{out_path}: {version}, {len(image)} bytes, signed")
+
+
+if __name__ == "__main__":
+    main()

scripts/ota_keygen.sh

@@ -0,0 +1,31 @@
+#!/usr/bin/env bash
+# Creates the Firmware Update signing key pair, once (ADR 0003).
+# The private key stays in ~/.config/roro9stack/ and must never be committed; the public key is
+# written into the firmware source. Losing the private key means the next update goes over USB.
+set -euo pipefail
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+KEY="${RORO_OTA_KEY:-$HOME/.config/roro9stack/ota-key.pem}"
+PUB_PEM="$ROOT/keys/ota-public.pem"
+PUB_H="$ROOT/src/platform/ota_public_key.h"
+
+if [ -e "$KEY" ]; then
+    echo "A signing key already exists at $KEY; not overwriting it." >&2
+    exit 1
+fi
+mkdir -p "$(dirname "$KEY")" "$ROOT/keys"
+( umask 077; openssl ecparam -name prime256v1 -genkey -noout -out "$KEY" )
+openssl ec -in "$KEY" -pubout -out "$PUB_PEM" 2>/dev/null
+
+{
+    echo "#pragma once"
+    echo ""
+    echo "// Public key that Firmware Updates must be signed for (ECDSA P-256). Generated by"
+    echo "// scripts/ota_keygen.sh; the private key is not in this repository (ADR 0003)."
+    echo "namespace roro {"
+    echo "inline constexpr char kOtaPublicKeyPem[] ="
+    sed 's/^/    "/; s/$/\\n"/' "$PUB_PEM"
+    echo "    ;"
+    echo "}  // namespace roro"
+} > "$PUB_H"
+echo "Private key: $KEY (keep it safe)"
+echo "Public key:  $PUB_PEM and $PUB_H (commit these)"

scripts/ota_push.py

@@ -0,0 +1,63 @@
+#!/usr/bin/env python3
+"""Pushes a signed Update File to a Cardputer over Wi-Fi (TCP 3232) and reports the result.
+
+Usage: scripts/ota_push.py <file.ota> <host>
+<host> is the device's IP (shown in Settings > Firmware).
+"""
+import socket
+import sys
+
+PORT = 3232
+
+
+def main():
+    if len(sys.argv) < 3:
+        sys.exit(__doc__)
+    path, host = sys.argv[1:3]
+    data = open(path, "rb").read()
+    try:
+        reply = push(data, host)
+    except (ConnectionResetError, BrokenPipeError):
+        # The device checks the header first and hangs up on a refused update mid-transfer.
+        print()
+        print("device: refused the update and closed the connection (the reason is on its screen)")
+        sys.exit(1)
+    print(f"device: {reply or '(no answer)'}")
+    sys.exit(0 if reply.startswith("OK") else 1)
+
+
+def push(data, host):
+    with socket.create_connection((host, PORT), timeout=15) as s:
+        s.settimeout(60)
+        sent, last = 0, -1
+        while sent < len(data):
+            chunk = data[sent:sent + 4096]
+            s.sendall(chunk)
+            sent += len(chunk)
+            pct = sent * 100 // len(data)
+            if pct != last:
+                print(f"\rsending {pct:3d}%", end="", flush=True)
+                last = pct
+        # The header announces the image size, so current firmware answers once it has it all.
+        # Firmware from before that change only knows the file ended when we half-close.
+        reply = b""
+        s.settimeout(3)
+        try:
+            reply = s.recv(256)
+        except socket.timeout:
+            s.shutdown(socket.SHUT_WR)
+            s.settimeout(60)
+        while reply == b"" or not reply.endswith(b"\n"):
+            try:
+                part = s.recv(256)
+            except socket.timeout:
+                break
+            if not part:
+                break
+            reply += part
+    print()
+    return reply.decode(errors="replace").strip()
+
+
+if __name__ == "__main__":
+    main()

scripts/rdbg.py

@@ -0,0 +1,281 @@
+#!/usr/bin/env python3
+"""The Debug Console of a Debug Build, over Wi-Fi (TCP 2323, see ADR 0004).
+
+Usage: scripts/rdbg.py [-H host] [-b] [command ...]
+  no command   interactive: type commands, see every console line live; Ctrl-D or `quit` leaves
+  command      runs it and prints what follows, until the console has been quiet for a moment
+  -H host      the device's IP (Settings > Firmware), default $RORO_OTA_HOST
+  -b           also print the backlog the device sends on connecting (boot messages and so on)
+
+Commands handled here as well as on the device:
+  crash                    the last crash, with its backtrace decoded (scripts/decode_backtrace.sh)
+  coredump [file]          fetch the core dump (default core-<date>.bin) and decode it with esp-coredump
+  get <card path> [file]   copy a file from the SD card
+  put <file> [card path]   copy a file to the SD card (default /updates/<name>), checked with SHA-256
+  screenshot [file.png]    what the screen shows (default screen-<date>.png), at 2x
+  reset                    restart at once, even if the main loop is stuck
+The token is read from ~/.config/roro9stack/debug-token (made by the first build).
+"""
+import hashlib
+import os
+import re
+import select
+import struct
+import subprocess
+import zlib
+import socket
+import sys
+import time
+
+PORT = 2323
+TOKEN_FILE = os.path.expanduser("~/.config/roro9stack/debug-token")
+
+
+def read_until(sock, marker, timeout):
+    """Everything up to and including `marker`, or None on a timeout or a closed connection."""
+    sock.settimeout(timeout)
+    data = b""
+    while marker not in data:
+        try:
+            chunk = sock.recv(4096)
+        except socket.timeout:
+            return None
+        if not chunk:
+            return None
+        data += chunk
+    return data
+
+
+def read_until_quiet(sock, quiet, out):
+    """Copies everything the device sends to `out` until nothing has arrived for `quiet` seconds."""
+    sock.settimeout(quiet)
+    while True:
+        try:
+            data = sock.recv(4096)
+        except socket.timeout:
+            return True
+        if not data:
+            return False
+        if out:
+            out.write(data.decode(errors="replace"))
+            out.flush()
+
+
+SCRIPTS = os.path.dirname(os.path.abspath(__file__))
+
+
+def run(sock, command, out=sys.stdout):
+    """Sends one command and returns its reply (also copied to `out`)."""
+    sock.sendall((command + "\n").encode())
+    # The main loop echoes "> command" when it runs it; the reply follows.
+    echoed = read_until(sock, f"> {command}\n".encode(), 15)
+    if echoed is None:
+        sys.exit("device: the command never ran")
+    reply = echoed.decode(errors="replace").split(f"> {command}\n", 1)[1]
+
+    class Tee:
+        def write(self, text):
+            nonlocal reply
+            reply += text
+            if out:
+                out.write(text)
+
+        def flush(self):
+            if out:
+                out.flush()
+
+    if out:
+        out.write(reply)
+    try:
+        read_until_quiet(sock, 1.5, Tee())
+    except BrokenPipeError:  # e.g. piped into head
+        pass
+    return reply
+
+
+def crash_firmware(reply):
+    """The archived-ELF key for the crashed firmware: its ELF digest, or else its version."""
+    sha = re.search(r"elf sha256 ([0-9a-f]{8,})", reply)
+    if sha:
+        return sha.group(1)
+    version = re.search(r"last one in (\S+)", reply)
+    return version.group(1) if version else None
+
+
+def crash(sock):
+    reply = run(sock, "crash")
+    trace = re.search(r"backtrace((?: 0x[0-9a-f]+)+)", reply)
+    key = crash_firmware(reply)
+    if trace and key:
+        print()
+        subprocess.call([os.path.join(SCRIPTS, "decode_backtrace.sh"), key] + trace.group(1).split())
+
+
+def coredump(sock, path):
+    info = run(sock, "crash", out=None)
+    sock.sendall(b"coredump get\n")
+    # One buffer throughout: the header, the size and the first bytes often share a packet.
+    buf = b""
+    sock.settimeout(15)
+    while b"coredump: none" not in buf and not re.search(rb"coredump: data (\d+)\n", buf):
+        chunk = sock.recv(65536)
+        if not chunk:
+            sys.exit("device: closed the connection")
+        buf += chunk
+    header = re.search(rb"coredump: data (\d+)\n", buf)
+    if not header:
+        sys.exit("device: no core dump in flash")
+    size = int(header.group(1))
+    data = buf[header.end():]
+    while len(data) < size:
+        chunk = sock.recv(65536)
+        if not chunk:
+            sys.exit(f"device: the connection closed after {len(data)} of {size} bytes")
+        data += chunk
+    data = data[:size]
+    path = path or time.strftime("core-%Y%m%d-%H%M%S.bin")
+    open(path, "wb").write(data)
+    print(f"saved {path} ({size} bytes)")
+    key = crash_firmware(info)
+    if key:
+        subprocess.call([os.path.join(SCRIPTS, "decode_coredump.sh"), path, key])
+
+
+def binary(sock, command, tag):
+    """Sends a binary command; returns (header words, payload) or exits with the device's error."""
+    sock.sendall((command + "\n").encode())
+    buf = b""
+    sock.settimeout(30)
+    pattern = re.compile(tag.encode() + rb": (data|ready|rgb332|error)([^\n]*)\n")
+    while not (m := pattern.search(buf)):
+        chunk = sock.recv(65536)
+        if not chunk:
+            sys.exit("device: closed the connection")
+        buf += chunk
+    if m.group(1) == b"error":
+        sys.exit(f"device: {tag}: error{m.group(2).decode()}")
+    return m.group(1).decode(), m.group(2).decode().split(), buf[m.end():]
+
+
+def receive(sock, have, size):
+    while len(have) < size:
+        chunk = sock.recv(65536)
+        if not chunk:
+            sys.exit(f"device: the connection closed after {len(have)} of {size} bytes")
+        have += chunk
+    return have[:size]
+
+
+def get(sock, remote, local):
+    _, words, rest = binary(sock, f"get {remote}", "get")
+    start, size = time.time(), int(words[0])
+    data = receive(sock, rest, size)
+    local = local or os.path.basename(remote)
+    open(local, "wb").write(data)
+    print(f"saved {local} ({size} bytes, {size / 1024 / max(time.time() - start, 0.001):.0f} KB/s)")
+
+
+def put(sock, local, remote):
+    data = open(local, "rb").read()
+    remote = remote or "/updates/" + os.path.basename(local)
+    digest = hashlib.sha256(data).hexdigest()
+    binary(sock, f"put {remote} {len(data)} {digest}", "put")
+    start = time.time()
+    sock.sendall(data)
+    answer = read_until(sock, b"\n", 30) or b"put: error no answer"
+    answer = answer.decode(errors="replace").strip().splitlines()[-1]
+    print(f"device: {answer} ({len(data) / 1024 / max(time.time() - start, 0.001):.0f} KB/s)")
+    if " error " in answer:
+        sys.exit(1)
+
+
+def png(path, width, height, rgb, scale):
+    rows = b""
+    for y in range(height):
+        row = b"".join(rgb[(y * width + x) * 3:(y * width + x) * 3 + 3] * scale for x in range(width))
+        rows += (b"\x00" + row) * scale
+    def chunk(kind, body):
+        return struct.pack(">I", len(body)) + kind + body + struct.pack(">I", zlib.crc32(kind + body))
+    header = struct.pack(">IIBBBBB", width * scale, height * scale, 8, 2, 0, 0, 0)
+    with open(path, "wb") as f:
+        f.write(b"\x89PNG\r\n\x1a\n" + chunk(b"IHDR", header) + chunk(b"IDAT", zlib.compress(rows)) + chunk(b"IEND", b""))
+
+
+def screenshot(sock, path):
+    _, words, rest = binary(sock, "screenshot", "screenshot")
+    width, height = int(words[0]), int(words[1])
+    pixels = receive(sock, rest, width * height)
+    # RGB332, as M5GFX stores an 8-bit sprite: RRRGGGBB.
+    rgb = b"".join(bytes(((v >> 5) * 255 // 7, ((v >> 2) & 7) * 255 // 7, (v & 3) * 255 // 3)) for v in pixels)
+    path = path or time.strftime("screen-%Y%m%d-%H%M%S.png")
+    png(path, width, height, rgb, 2)
+    print(f"saved {path} ({width * 2}x{height * 2})")
+
+
+def interactive(sock):
+    sock.setblocking(False)
+    while True:
+        ready, _, _ = select.select([sock, sys.stdin], [], [])
+        if sock in ready:
+            data = sock.recv(4096)
+            if not data:
+                print("\n(connection closed)")
+                return
+            sys.stdout.write(data.decode(errors="replace"))
+            sys.stdout.flush()
+        if sys.stdin in ready:
+            line = sys.stdin.readline()
+            if not line:
+                return
+            sock.sendall(line.encode())
+
+
+def main():
+    args = sys.argv[1:]
+    host, backlog = os.environ.get("RORO_OTA_HOST"), False
+    while args and args[0].startswith("-"):
+        flag = args.pop(0)
+        if flag == "-H" and args:
+            host = args.pop(0)
+        elif flag == "-b":
+            backlog = True
+        else:
+            sys.exit(__doc__)
+    if not host:
+        sys.exit("No device: pass -H <ip> or set RORO_OTA_HOST\n\n" + __doc__)
+    token = open(TOKEN_FILE).read().strip()
+
+    with socket.create_connection((host, PORT), timeout=10) as sock:
+        sock.sendall((token + "\n").encode())
+        # The device may still be finishing a previous client: wait for this connection's banner.
+        banner = read_until(sock, b"Backlog follows.\n", 15)
+        if banner is None:
+            sys.exit("device: no banner (wrong token, or another client is connected)")
+        show = sys.stdout if backlog or not args else None
+        if show:
+            show.write(banner.decode(errors="replace"))
+        read_until_quiet(sock, 0.5, show)  # the backlog
+        if not args:
+            return interactive(sock)
+        if args == ["crash"]:
+            return crash(sock)
+        if args[0] == "get" and len(args) >= 2:
+            return get(sock, args[1], args[2] if len(args) > 2 else None)
+        if args[0] == "put" and len(args) >= 2:
+            return put(sock, args[1], args[2] if len(args) > 2 else None)
+        if args[0] == "screenshot":
+            return screenshot(sock, args[1] if len(args) > 1 else None)
+        if args == ["reset"]:  # answered by the console's own task, not the main loop
+            sock.sendall(b"reset\n")
+            print((read_until(sock, b"restarting now\n", 10) or b"device: no answer").decode().strip().splitlines()[-1])
+            return
+        if args[0] == "coredump" and args[1:2] != ["erase"]:
+            return coredump(sock, args[1] if len(args) > 1 else None)
+        run(sock, " ".join(args))
+
+
+if __name__ == "__main__":
+    try:
+        main()
+    except (ConnectionResetError, BrokenPipeError):
+        sys.exit("device: the connection dropped (restarting?)")

scripts/sd_put.py

@@ -0,0 +1,79 @@
+#!/usr/bin/env python3
+"""Copies a file to the Cardputer's SD card over the USB serial console (the `sd put` command).
+
+Usage: scripts/sd_put.sh <file> [card path]
+The card path defaults to /updates/<file name>, where Settings > Firmware finds Update Files.
+The device acknowledges each chunk once it's on the card, checks the SHA-256 of the whole file,
+and only then renames <card path>.part to <card path>.
+"""
+import glob
+import hashlib
+import os
+import sys
+import time
+
+import serial
+
+DEBUG = bool(os.environ.get("SD_PUT_DEBUG"))  # also show the console lines in between
+
+
+def find_port():
+    ports = sorted(glob.glob("/dev/serial/by-id/*Espressif*"))
+    return os.path.realpath(ports[0]) if ports else None
+
+
+def reply(port, timeout):
+    """The next `sd put:` line from the device; everything else on the console is skipped."""
+    deadline = time.time() + timeout
+    while time.time() < deadline:
+        line = port.readline().decode(errors="replace").strip()
+        if line.startswith("sd put:"):
+            return line[len("sd put:"):].strip()
+        if line and DEBUG:
+            print(f"\n  console: {line}", file=sys.stderr)
+    return "error no answer from the device"
+
+
+def fail(answer):
+    print()
+    sys.exit(f"device: {answer}")
+
+
+def main():
+    if len(sys.argv) < 2:
+        sys.exit(__doc__)
+    path = sys.argv[1]
+    dest = sys.argv[2] if len(sys.argv) > 2 else "/updates/" + os.path.basename(path)
+    port_name = find_port()
+    if not port_name:
+        sys.exit("No Cardputer found on USB")
+    data = open(path, "rb").read()
+    sha = hashlib.sha256(data).hexdigest()
+
+    with serial.Serial(port_name, 115200, timeout=0.5) as port:
+        port.reset_input_buffer()
+        # The leading newline ends any half-typed command.
+        port.write(f"\nsd put {dest} {len(data)} {sha}\n".encode())
+        answer = reply(port, 10)
+        if not answer.startswith("ready "):
+            fail(answer)
+        chunk = int(answer.split()[1])
+
+        start, sent = time.time(), 0
+        while sent < len(data):
+            port.write(data[sent:sent + chunk])
+            sent = min(sent + chunk, len(data))
+            print(f"\rsending {sent * 100 // len(data):3d}%", end="", flush=True)
+            if sent < len(data):
+                answer = reply(port, 10)
+                if answer != f"ok {sent}":
+                    fail(answer)
+        answer = reply(port, 15)
+        if not answer.startswith("done "):
+            fail(answer)
+        seconds = time.time() - start
+        print(f"\rdevice: {answer}, {seconds:.1f} s ({len(data) / 1024 / seconds:.0f} KB/s)")
+
+
+if __name__ == "__main__":
+    main()

scripts/sd_put.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+# Copy a file to the Cardputer's SD card over USB serial, e.g. an Update File into /updates.
+# Usage: scripts/sd_put.sh <file> [card path]   (default card path: /updates/<file name>)
+set -euo pipefail
+source "$(dirname "$0")/_docker.sh"
+[ -f "${1:-}" ] || { echo "Usage: scripts/sd_put.sh <file> [card path]" >&2; exit 1; }
+docker rm -f roro9stack-serial >/dev/null 2>&1 || true  # a serial log would hold the port
+FILE="$(realpath "$1")"
+DOCKER_EXTRA=(-e SD_PUT_DEBUG="${SD_PUT_DEBUG:-}" --group-add "$(getent group dialout | cut -d: -f3)" --privileged -v /dev:/dev -v "$(dirname "$FILE"):/in:ro")
+run_in_container /pio/penv/bin/python scripts/sd_put.py "/in/$(basename "$FILE")" "${@:2}"

scripts/version.py

@@ -10,4 +10,24 @@ try:
 except Exception:
     version = "unknown"
 
+if env["PIOENV"].endswith("-debug"):  # noqa: F821
+    version += "+debug"  # a Debug Build says so wherever the version shows
+
 env.Append(CPPDEFINES=[("RORO_VERSION", '\\"%s\\"' % version)])  # noqa: F821
+
+
+# Keep every build's ELF, named by version and the first 16 hex digits of its SHA-256 (the core dump
+# names the crashed firmware by the same digest), so a crash can be decoded after later builds.
+def archive_elf(source, target, env):
+    import hashlib
+    import os
+    import shutil
+
+    elf = str(target[0])
+    digest = hashlib.sha256(open(elf, "rb").read()).hexdigest()[:16]
+    folder = os.path.join(env.subst("$PROJECT_DIR"), ".pio", "elves")
+    os.makedirs(folder, exist_ok=True)
+    shutil.copy(elf, os.path.join(folder, "%s.%s.elf" % (version, digest)))
+
+
+env.AddPostAction("$BUILD_DIR/${PROGNAME}.elf", archive_elf)  # noqa: F821

src/apps/firmware_page.cpp

@@ -0,0 +1,101 @@
+#include "firmware_page.h"
+
+#include <SD.h>
+
+#include "ui/widgets.h"
+#include "version.h"
+
+namespace roro {
+
+namespace {
+constexpr const char* kUpdatesFolder = "/updates";
+
+bool endsWith(const std::string& s, const std::string& suffix) {
+    return s.size() >= suffix.size() && s.compare(s.size() - suffix.size(), suffix.size(), suffix) == 0;
+}
+}  // namespace
+
+void FirmwarePage::enter() {
+    confirm_.reset();
+    {
+        std::lock_guard<std::mutex> g(lock_);
+        files_.clear();
+        listed_ = false;
+    }
+    list_.setCount(kFixed);
+    storage_.runJob([this]() {
+        std::vector<std::string> found;
+        File dir = SD.open(kUpdatesFolder);
+        if (dir && dir.isDirectory())
+            for (File f = dir.openNextFile(); f; f = dir.openNextFile())
+                if (!f.isDirectory() && endsWith(f.name(), ".ota")) found.push_back(std::string(kUpdatesFolder) + "/" + f.name());
+        std::lock_guard<std::mutex> g(lock_);
+        files_ = found;
+        listed_ = true;
+    });
+}
+
+std::vector<std::string> FirmwarePage::files() {
+    std::lock_guard<std::mutex> g(lock_);
+    return files_;
+}
+
+bool FirmwarePage::onKey(const KeyEvent& e) {
+    auto found = files();
+    if (confirm_) {
+        confirm_->onKey(e);
+        int pick = list_.selected() - kFixed;
+        if (confirm_->result() == 1 && pick >= 0 && pick < static_cast<int>(found.size())) update_.installFromSd(found[pick]);
+        if (confirm_->result() != DialogModel::kPending) confirm_.reset();
+        return true;
+    }
+    list_.setCount(kFixed + static_cast<int>(found.size()));
+    switch (e.key) {
+        case Key::Up: list_.up(); break;
+        case Key::Down: list_.down(); break;
+        case Key::Back: return false;
+        case Key::Select:
+            if (list_.selected() >= kFixed) confirm_.reset(new DialogModel({"Cancel", "Install"}));
+            break;
+        default: break;
+    }
+    return true;
+}
+
+void FirmwarePage::draw(Canvas& c) {
+    auto found = files();
+    bool listed;
+    {
+        std::lock_guard<std::mutex> g(lock_);
+        listed = listed_;
+    }
+    list_.setCount(kFixed + static_cast<int>(found.size()));
+    std::string ip = wifi_.ip();
+    widgets::list(
+        c, list_, theme::kContent,
+        [&](int i) -> std::string {
+            switch (i) {
+                case kVersion: return "Version";
+                case kStatus: return "Status";
+                case kAddress: return "Push to";
+                case kSdHeader: return listed ? (found.empty() ? "No .ota files in /updates" : "On the SD card:") : "Looking on the SD card...";
+                default: return "  " + found[i - kFixed].substr(std::string(kUpdatesFolder).size() + 1);
+            }
+        },
+        [&](int i) -> std::string {
+            switch (i) {
+                case kVersion: return versionString();
+                case kStatus: return update_.onProbation() ? "on probation" : "confirmed";
+                case kAddress: return ip.empty() ? "Wi-Fi not connected" : ip + ":" + std::to_string(UpdateService::kPort);
+                case kSdHeader: return "";
+                default: return "install >";
+            }
+        });
+    if (confirm_) {
+        int pick = list_.selected() - kFixed;
+        std::string name = pick >= 0 && pick < static_cast<int>(found.size()) ? found[pick] : "";
+        widgets::dialog(c, "Install update?", name + " is checked before anything is written. The device restarts after.", *confirm_);
+    }
+}
+
+}  // namespace roro

src/apps/firmware_page.h

@@ -0,0 +1,47 @@
+#pragma once
+
+#include <memory>
+#include <mutex>
+#include <string>
+#include <vector>
+
+#include "dialog_model.h"
+#include "key_event.h"
+#include "list_model.h"
+#include "services/storage_service.h"
+#include "services/update_service.h"
+#include "services/wifi_service.h"
+#include "ui/canvas.h"
+#include "ui/theme.h"
+
+namespace roro {
+
+// Settings → Firmware: the running version and its Probation, where to push Firmware Updates, and
+// the Update Files on the SD card (in /updates) to install from.
+class FirmwarePage {
+   public:
+    FirmwarePage(UpdateService& update, WifiService& wifi, StorageService& storage)
+        : update_(update), wifi_(wifi), storage_(storage) {}
+
+    void enter();
+    bool onKey(const KeyEvent& e);  // false: leave the page
+    void draw(Canvas& c);
+
+   private:
+    enum Row { kVersion, kStatus, kAddress, kSdHeader, kFixed };
+
+    std::vector<std::string> files();
+
+    UpdateService& update_;
+    WifiService& wifi_;
+    StorageService& storage_;
+    ListModel list_{theme::kContent.h / theme::kLineHeight};
+    std::unique_ptr<DialogModel> confirm_;
+
+    // Filled on the storage task.
+    std::mutex lock_;
+    std::vector<std::string> files_;
+    bool listed_ = false;
+};
+
+}  // namespace roro

src/apps/gemini_app.cpp

@@ -0,0 +1,527 @@
+#include "gemini_app.h"
+
+#include <Arduino.h>
+
+#include <algorithm>
+
+#include "gemini_url.h"
+#include "text_wrap.h"
+#include "ui/fonts.h"
+#include "ui/theme.h"
+#include "ui/widgets.h"
+
+namespace roro {
+
+using namespace gemini;
+
+namespace {
+
+constexpr int kUrlBar = 10;  // the small line with the URL at the top
+constexpr int kMargin = 3;
+constexpr const char* kStartUrl = GeminiService::kStartUrl;
+constexpr size_t kMaxHistory = 20;  // Q77
+
+// How each line type looks: its prefix, the indent of its wrapped rows, font and colour.
+struct Style {
+    const char* prefix;
+    int indent;  // characters
+    const lgfx::U8g2font* font;
+    uint16_t color;
+};
+
+Style styleOf(LineType t) {
+    switch (t) {
+        case LineType::Heading1: return {"", 0, &fonts::bold, theme::kAccent};
+        case LineType::Heading2: return {"", 0, &fonts::bold, theme::kText};
+        case LineType::Heading3: return {"", 0, &fonts::bold, theme::kMuted};
+        case LineType::ListItem: return {"\xC2\xB7 ", 2, &fonts::body, theme::kText};  // ·
+        case LineType::Quote: return {"> ", 2, &fonts::body, theme::kMuted};
+        case LineType::Link: return {"\xC2\xBB ", 2, &fonts::body, theme::kAccent};    // »
+        case LineType::Preformatted: return {"", 0, &fonts::body, theme::kText};
+        default: return {"", 0, &fonts::body, theme::kText};
+    }
+}
+
+}  // namespace
+
+void GeminiApp::onEnter() {
+    if (page_.url.empty() && !loading_) navigate(kStartUrl, false);
+    requestRedraw();
+}
+
+// The page's first heading, for a bookmark's label.
+std::string GeminiApp::titleOf() const {
+    for (size_t i = 0; i < page_.text.lineCount() && i < 40; i++)
+        if (static_cast<LineType>(types_[i]) == LineType::Heading1) return lineAt(i).text;
+    return "";
+}
+
+void GeminiApp::follow(const std::string& link) {
+    std::string url = resolve(page_.base(), link);
+    navigate(url, true, isSaved());  // inside a Saved Page, its saved links open offline (Q84)
+}
+
+void GeminiApp::showMessage(const std::string& url, const std::string& gemtext) {
+    GeminiPage p;
+    p.outcome = GeminiPage::Outcome::Ok;
+    p.url = url;
+    p.header.status = 20;
+    p.text.append(gemtext.data(), gemtext.size());
+    p.text.finish();
+    show(std::move(p));
+}
+
+void GeminiApp::navigate(const std::string& target, bool remember, bool preferSaved) {
+    bool local = target == kStartUrl || target.rfind("file://", 0) == 0;
+    if (!isGemini(target) && !local) {
+        status_ = "Not Gemini: " + target;
+        statusMs_ = millis();
+        requestRedraw();
+        return;
+    }
+    if (!gemini_.fetch(target, preferSaved)) {
+        status_ = "Busy: try again in a moment";
+        statusMs_ = millis();
+        return;
+    }
+    if (remember && !page_.url.empty()) {
+        history_.push_back({page_.url, topRow_});
+        if (history_.size() > kMaxHistory) history_.erase(history_.begin());
+    }
+    loading_ = true;
+    loadingUrl_ = target;
+    status_.clear();
+    requestRedraw();
+}
+
+void GeminiApp::show(GeminiPage&& page) {
+    page_ = std::move(page);
+    windowLoading_ = false;
+    analyse();
+    topRow_ = hscroll_ = 0;
+    selected_ = -1;
+}
+
+void GeminiApp::analyse() {
+    types_.clear();
+    links_.clear();
+    // A window may start inside a preformatted block: the index says (bit 31).
+    size_t entry = page_.windowStart / GeminiService::kIndexEvery;
+    bool pre = page_.windowed && entry < page_.lineIndex.size() && (page_.lineIndex[entry] & 0x80000000u);
+    for (size_t i = 0; i < page_.text.lineCount(); i++) {
+        LineType t = parseGemLine(page_.text.line(i), pre).type;
+        if (page_.header.mimeType() != "text/gemini") t = LineType::Preformatted;  // other text/*: as is
+        types_.push_back(static_cast<uint8_t>(t));
+        if (t == LineType::Link) links_.push_back(i);
+    }
+    layoutDirty_ = true;
+    requestRedraw();
+}
+
+size_t GeminiApp::topLine() const {
+    if (firstRow_.size() < 2) return page_.windowStart;
+    size_t i = std::upper_bound(firstRow_.begin(), firstRow_.end() - 1, static_cast<uint32_t>(topRow_)) - firstRow_.begin();
+    return page_.windowStart + (i > 0 ? i - 1 : 0);
+}
+
+void GeminiApp::requestWindow(size_t firstLine) {
+    if (windowLoading_ || !gemini_.loadWindow(page_, firstLine)) return;
+    windowLoading_ = true;
+    keepLine_ = static_cast<long>(topLine());
+    status_ = "Reading from the card...";
+    statusMs_ = millis();
+}
+
+// A new window of the same page: same URL, history and position, other lines.
+void GeminiApp::applyWindow(GeminiPage&& window) {
+    windowLoading_ = false;
+    status_.clear();
+    page_.text = std::move(window.text);
+    page_.windowStart = window.windowStart;
+    page_.lineIndex = std::move(window.lineIndex);
+    selected_ = -1;
+    analyse();
+}
+
+void GeminiApp::update(uint32_t nowMs) {
+    GeminiPage result;
+    bool got = gemini_.takeResult(result);
+    if (got && !result.windowOf.empty()) {
+        windowLoading_ = false;
+        if (result.windowOf == page_.backing) applyWindow(std::move(result));  // else: we've moved on
+    } else if (got) {
+        loading_ = false;
+        std::string url = result.url;
+        switch (result.outcome) {
+            case GeminiPage::Outcome::CertificateChanged:
+                pendingCert_ = std::move(result);
+                certDialog_.reset(new DialogModel({"Cancel", "Trust it"}));
+                break;
+            case GeminiPage::Outcome::Failed:
+                showMessage(url, "# Can't open this page\n" + result.error + "\n=> " + url + " Try again\n");
+                break;
+            case GeminiPage::Outcome::Ok:
+                switch (result.header.category()) {
+                    case Category::Success:
+                        if (result.header.mimeType().rfind("text/", 0) == 0) show(std::move(result));
+                        else {
+                            std::string mime = result.header.mimeType();
+                            showMessage(url, "# Not a text page\nThis is " + mime +
+                                                 ", which the Cardputer can't show. s saves it to the card, in "
+                                                 "/gemini/downloads.\n");
+                            page_.header.meta = mime;  // so s knows to download it
+                        }
+                        break;
+                    case Category::Input:
+                        // Q72: ask, then request the same URL with the answer as its query.
+                        inputOpen_ = true;
+                        inputSensitive_ = result.header.sensitiveInput();
+                        inputPrompt_ = result.header.meta;
+                        inputUrl_ = url;
+                        input_.setText("");
+                        break;
+                    default:
+                        showMessage(url, "# " + std::to_string(result.header.status) + " " + result.header.meta +
+                                             "\nThe server refused this page.\n=> " + url + " Try again\n");
+                        break;
+                }
+                break;
+        }
+        requestRedraw();
+    }
+    // Signed: statusMs_ may be a few ms ahead of this pass's nowMs (set by a key handled after it).
+    std::string message;
+    if (gemini_.takeMessage(message)) {
+        status_ = message;
+        statusMs_ = millis();
+        if (!reopen_.empty()) {  // a refreshed Saved Page: show the new copy
+            navigate(reopen_, false);
+            reopen_.clear();
+        } else if (message == "Deleted") navigate(kStartUrl, false);
+        requestRedraw();
+    }
+    if (!status_.empty() && static_cast<int32_t>(nowMs - statusMs_) > 4000) {
+        status_.clear();
+        requestRedraw();
+    }
+}
+
+int GeminiApp::rowsOnScreen() const { return (theme::kContent.h - kUrlBar) / theme::kLineHeight; }
+
+LineType typeOf(const std::vector<uint8_t>& types, size_t i) { return static_cast<LineType>(types[i]); }
+
+GemLine GeminiApp::lineAt(size_t i) const {
+    bool pre = typeOf(types_, i) == LineType::Preformatted;
+    GemLine g = parseGemLine(page_.text.line(i), pre);
+    if (typeOf(types_, i) == LineType::Preformatted) {
+        g.type = LineType::Preformatted;
+        g.text = page_.text.line(i);
+    }
+    return g;
+}
+
+// A line's rows, as drawn: prefix on the first, indent on the rest; preformatted lines don't wrap.
+std::vector<std::string> GeminiApp::rowsOf(Canvas& c, size_t i) const {
+    GemLine g = lineAt(i);
+    if (g.type == LineType::PreToggle) return {};
+    if (g.type == LineType::Preformatted) return {displayText(g.text)};
+    Style st = styleOf(g.type);
+    c.setFont(st.font);
+    MeasureText measure = [&c](const std::string& s) { return static_cast<int>(c.textWidth(s.c_str())); };
+    int width = theme::kWidth - 2 * kMargin;
+    std::string indent(st.indent, ' ');
+    std::vector<std::string> rows = wrapText(st.prefix + displayText(g.text), width, measure);
+    if (rows.empty()) rows.push_back("");
+    // Rows after the first: the exact rest of the text (wrapText keeps every space but the one it
+    // breaks at), wrapped again, narrower, behind the indent.
+    if (rows.size() > 1 && st.indent > 0) {
+        std::string full = st.prefix + displayText(g.text);
+        std::string rest = full.substr(rows[0].size());
+        if (!rest.empty() && rest[0] == ' ') rest.erase(0, 1);
+        std::vector<std::string> more = wrapText(rest, width - measure(indent), measure);
+        rows.resize(1);
+        for (auto& m : more) rows.push_back(indent + m);
+    }
+    return rows;
+}
+
+void GeminiApp::layout(Canvas& c) {
+    firstRow_.assign(page_.text.lineCount() + 1, 0);
+    uint32_t row = 0;
+    for (size_t i = 0; i < page_.text.lineCount(); i++) {
+        firstRow_[i] = row;
+        row += rowsOf(c, i).size();
+    }
+    firstRow_.back() = row;
+    layoutDirty_ = false;
+}
+
+void GeminiApp::scrollTo(int row) {
+    int total = firstRow_.empty() ? 0 : static_cast<int>(firstRow_.back());
+    // A windowed page: near either end of the window, read the next part from the card. The new
+    // window starts a block before the line on top, so what's on screen stays.
+    const size_t block = GeminiService::kIndexEvery;
+    if (row + rowsOnScreen() > total - 2 && moreBelow()) {
+        size_t line = topLine();
+        requestWindow(line >= block ? line - line % block : 0);
+    } else if (row < 0 && moreAbove()) {
+        size_t line = topLine();
+        size_t back = page_.text.lineCount() / 2;  // about half a window above
+        requestWindow(line > back ? line - back : 0);
+    }
+    topRow_ = std::max(0, std::min(row, std::max(0, total - rowsOnScreen())));
+    requestRedraw();
+}
+
+void GeminiApp::selectLink(int direction) {
+    // A windowed page: past the window's last (or first) link, page on instead of wrapping.
+    int last = static_cast<int>(links_.size()) - 1;
+    if ((direction > 0 && moreBelow() && (links_.empty() || selected_ == last)) ||
+        (direction < 0 && moreAbove() && (links_.empty() || selected_ == 0))) {
+        selected_ = -1;
+        scrollTo(topRow_ + direction * (rowsOnScreen() - 1));
+        return;
+    }
+    if (links_.empty()) return;
+    int count = static_cast<int>(links_.size());
+    if (selected_ < 0) {
+        // The first link on screen, or after it when going forward.
+        selected_ = direction > 0 ? 0 : count - 1;
+        for (int k = 0; k < count; k++)
+            if (static_cast<int>(firstRow_[links_[k]]) >= topRow_) {
+                selected_ = direction > 0 ? k : std::max(0, k - 1);
+                break;
+            }
+    } else selected_ = (selected_ + direction + count) % count;
+    int row = firstRow_[links_[selected_]];
+    if (row < topRow_ || row >= topRow_ + rowsOnScreen()) scrollTo(row - 1);
+    requestRedraw();
+}
+
+bool GeminiApp::onKey(const KeyEvent& e) {
+    requestRedraw();
+    if (certDialog_) {
+        certDialog_->onKey(e);
+        if (certDialog_->result() == DialogModel::kPending) return true;
+        if (certDialog_->result() == 1) {
+            gemini_.trust(pendingCert_.host, pendingCert_.port, pendingCert_.presented);
+            navigate(pendingCert_.requested, false);
+        }
+        certDialog_.reset();
+        return true;
+    }
+    if (deleteDialog_) {
+        deleteDialog_->onKey(e);
+        if (deleteDialog_->result() == DialogModel::kPending) return true;
+        if (deleteDialog_->result() == 1) gemini_.deleteSaved(savedPathOf());
+        deleteDialog_.reset();
+        return true;
+    }
+    if (inputOpen_) {
+        switch (e.key) {
+            case Key::Char: input_.insert(e.ch); break;
+            case Key::Delete: input_.backspace(); break;
+            case Key::Left: input_.left(); break;
+            case Key::Right: input_.right(); break;
+            case Key::Back: inputOpen_ = false; break;
+            case Key::Select:
+                inputOpen_ = false;
+                navigate(resolve(inputUrl_, "?" + encodeQuery(input_.text())));
+                break;
+            default: break;
+        }
+        return true;
+    }
+    if (addressOpen_) {
+        switch (e.key) {
+            case Key::Char: address_.insert(e.ch); break;
+            case Key::Delete: address_.backspace(); break;
+            case Key::Left: address_.left(); break;
+            case Key::Right: address_.right(); break;
+            case Key::Back: addressOpen_ = false; break;
+            case Key::Select: {
+                std::string url = address_.text();
+                if (url.find("://") == std::string::npos) url = "gemini://" + url;
+                addressOpen_ = false;
+                navigate(url);
+                break;
+            }
+            default: break;
+        }
+        return true;
+    }
+    switch (e.key) {
+        case Key::Up: scrollTo(topRow_ - 1); return true;
+        case Key::Down: scrollTo(topRow_ + 1); return true;
+        case Key::Left: hscroll_ = std::max(0, hscroll_ - 8); return true;
+        case Key::Right: hscroll_ += 8; return true;
+        case Key::Tab: selectLink(e.shift ? -1 : 1); return true;
+        case Key::Select:
+            if (selected_ >= 0) follow(lineAt(links_[selected_]).url);
+            return true;
+        case Key::Back:
+        case Key::Delete:
+            if (loading_) {
+                gemini_.cancel();
+                return true;
+            }
+            if (history_.empty()) return e.key == Key::Delete;  // Back leaves the App
+            {
+                Visit v = history_.back();
+                history_.pop_back();
+                navigate(v.url, false);
+                restoreRow_ = v.topRow;
+            }
+            return true;
+        case Key::Char:
+            switch (e.ch) {
+                case ' ': scrollTo(topRow_ + rowsOnScreen() - 1); break;
+                case 'g':
+                    address_.setText(page_.url == kStartUrl || isSaved() ? "" : page_.url);
+                    addressOpen_ = true;
+                    break;
+                case 'b':  // Q77
+                    if (isGemini(page_.base())) gemini_.addBookmark(page_.base(), titleOf());
+                    break;
+                case 's':  // Q82, Q73
+                    if (isSaved()) status_ = "Already saved; r refreshes it";
+                    else if (!isGemini(page_.url)) status_ = "Only Gemini pages can be saved";
+                    else if (page_.header.mimeType().rfind("text/", 0) == 0) gemini_.save(page_.url);
+                    else gemini_.download(page_.url);
+                    statusMs_ = millis();
+                    break;
+                case 'S': {  // Q83: this page and the gemtext it links to on the same capsule
+                    Url here;
+                    if (isSaved() || !parseUrl(page_.url, here)) break;
+                    std::vector<std::string> links;
+                    for (uint32_t i : links_) {
+                        std::string target = resolve(page_.url, lineAt(i).url);
+                        Url u;
+                        if (isGemini(target) && parseUrl(target, u) && u.host == here.host && target != page_.url &&
+                            std::find(links.begin(), links.end(), target) == links.end())
+                            links.push_back(target);
+                        if (static_cast<int>(links.size()) >= GeminiService::kMaxLinkedPages - 1) break;
+                    }
+                    gemini_.saveWithLinks(page_.url, links);
+                    break;
+                }
+                case 'r':  // Q84: a fresh copy of a Saved Page
+                    if (isSaved() && gemini_.refresh(savedPathOf())) reopen_ = page_.url;
+                    break;
+                case 'd':  // Q85
+                    if (isSaved()) deleteDialog_.reset(new DialogModel({"Keep", "Delete"}));
+                    break;
+                default: break;
+            }
+            return true;
+        default: return false;
+    }
+}
+
+void GeminiApp::draw(Canvas& c) {
+    const auto& area = theme::kContent;
+    if (layoutDirty_) {
+        layout(c);
+        if (restoreRow_ >= 0 && !loading_) {
+            scrollTo(restoreRow_);
+            restoreRow_ = -1;
+        }
+        if (keepLine_ >= 0 && !windowLoading_) {  // a new window: back to the line that was on top
+            long local = keepLine_ - static_cast<long>(page_.windowStart);
+            if (local >= 0 && local < static_cast<long>(page_.text.lineCount())) topRow_ = firstRow_[local];
+            keepLine_ = -1;
+        }
+    }
+
+    // The URL bar: what's shown, or what's loading, or a passing message.
+    c.setFont(&fonts::small);
+    c.setTextDatum(top_left);
+    std::string bar = loading_ ? "Loading " + loadingUrl_
+                      : !status_.empty() ? status_
+                      : isSaved() ? "saved " + page_.savedOn + ": " + page_.savedFrom
+                                  : page_.url;
+    c.setTextColor(loading_ || !status_.empty() ? theme::kWarning : theme::kMuted);
+    c.drawString(displayText(bar).substr(0, 47).c_str(), kMargin, area.y + 1);
+
+    int rows = rowsOnScreen(), y0 = area.y + kUrlBar;
+    // The first source line on screen: the last whose first row is at or above topRow_.
+    size_t i = std::upper_bound(firstRow_.begin(), firstRow_.end() - 1, static_cast<uint32_t>(topRow_)) -
+               firstRow_.begin();
+    i = i > 0 ? i - 1 : 0;
+    int row = topRow_;
+    while (i < page_.text.lineCount() && row < topRow_ + rows) {
+        int skip = row - static_cast<int>(firstRow_[i]);
+        int lineRows = static_cast<int>(firstRow_[i + 1] - firstRow_[i]);
+        if (lineRows > 0) {
+            drawLine(c, i, skip, y0 + (row - topRow_) * theme::kLineHeight, topRow_ + rows - row);
+            row += lineRows - skip;
+        }
+        i++;
+    }
+    if (page_.truncated && row < topRow_ + rows) {
+        c.setFont(&fonts::small);
+        c.setTextColor(theme::kWarning);
+        c.drawString(("Cut short: " + page_.truncatedWhy).substr(0, 47).c_str(), kMargin,
+                     y0 + (row - topRow_) * theme::kLineHeight + 2);
+    }
+    // Scroll position, on the right edge: over the whole page, also when only a window is in memory.
+    int total = static_cast<int>(firstRow_.back());
+    int h = area.h - kUrlBar;
+    if (page_.windowed && page_.totalLines > 0) {
+        int barH = std::max(6, static_cast<int>(h * page_.text.lineCount() / page_.totalLines / 3));
+        int y = static_cast<int>((h - barH) * topLine() / std::max<size_t>(1, page_.totalLines - 1));
+        c.fillRect(area.w - 2, y0 + y, 2, barH, theme::kMuted);
+    } else if (total > rows) {
+        int barH = std::max(6, h * rows / total);
+        c.fillRect(area.w - 2, y0 + (h - barH) * topRow_ / std::max(1, total - rows), 2, barH, theme::kMuted);
+    }
+
+    if (addressOpen_) {
+        theme::Rect box{2, area.y + area.h / 2 - 12, area.w - 4, theme::kLineHeight + 4};
+        c.fillRect(box.x - 2, box.y - 12, box.w + 4, box.h + 14, theme::kBackground);
+        c.setFont(&fonts::small);
+        c.setTextColor(theme::kMuted);
+        c.drawString("Go to (Enter, or ` to cancel)", box.x, box.y - 10);
+        widgets::lineEditor(c, address_, box);
+    }
+    if (inputOpen_) {
+        theme::Rect box{2, area.y + area.h / 2 - 4, area.w - 4, theme::kLineHeight + 4};
+        c.fillRect(0, box.y - 26, area.w, box.h + 28, theme::kBackground);
+        c.setFont(&fonts::body);
+        c.setTextColor(theme::kText);
+        c.drawString(displayText(inputPrompt_).substr(0, 39).c_str(), box.x, box.y - 22);
+        c.setFont(&fonts::small);
+        c.setTextColor(theme::kMuted);
+        c.drawString(inputSensitive_ ? "(hidden) Enter sends, ` cancels" : "Enter sends, ` cancels", box.x, box.y - 9);
+        if (inputSensitive_) {
+            LineEditor masked(1024);
+            masked.setText(std::string(input_.text().size(), '*'));
+            widgets::lineEditor(c, masked, box);
+        } else widgets::lineEditor(c, input_, box);
+    }
+    if (deleteDialog_) widgets::dialog(c, "Delete this Saved Page?", page_.savedFrom, *deleteDialog_);
+    if (certDialog_)
+        widgets::dialog(c, "Certificate changed",
+                        pendingCert_.host + " now shows a different certificate. Was " + pendingCert_.pinned.substr(0, 16) +
+                            "..., now " + pendingCert_.presented.substr(0, 16) + "...",
+                        *certDialog_);
+}
+
+void GeminiApp::drawLine(Canvas& c, size_t i, int firstRow, int y, int rowsLeft) {
+    GemLine g = lineAt(i);
+    Style st = styleOf(g.type);
+    bool isSelected = selected_ >= 0 && links_[selected_] == i;
+    std::vector<std::string> rows = rowsOf(c, i);
+    c.setFont(st.font);
+    c.setTextDatum(top_left);
+    for (int r = firstRow; r < static_cast<int>(rows.size()) && r - firstRow < rowsLeft; r++) {
+        int ry = y + (r - firstRow) * theme::kLineHeight;
+        if (isSelected) c.fillRect(0, ry, theme::kWidth - 3, theme::kLineHeight, theme::kSelection);
+        c.setTextColor(isSelected ? theme::kText : st.color);
+        std::string text = rows[r];
+        if (g.type == LineType::Preformatted) text = hscroll_ < static_cast<int>(text.size()) ? text.substr(hscroll_) : "";
+        c.drawString(text.c_str(), kMargin, ry + 1);
+    }
+}
+
+}  // namespace roro

src/apps/gemini_app.h

@@ -0,0 +1,81 @@
+#pragma once
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "app.h"
+#include "dialog_model.h"
+#include "gemtext.h"
+#include "line_editor.h"
+#include "services/gemini_service.h"
+#include "ui/canvas.h"
+
+namespace roro {
+
+// Geminispace on the Cardputer (docs/milestones/G1.md). Pages come from the GeminiService as
+// lines; the App wraps them once (keeping only each line's first row), then wraps just the lines
+// on screen when it draws, so a long page costs 4 bytes a line on top of its text.
+class GeminiApp : public App {
+   public:
+    explicit GeminiApp(GeminiService& gemini) : gemini_(gemini) {}
+    void onEnter() override;
+    bool onKey(const KeyEvent& e) override;
+    bool textEntryActive() const override { return addressOpen_ || inputOpen_; }
+    void update(uint32_t nowMs) override;
+    void draw(Canvas& c) override;
+
+   private:
+    struct Visit {
+        std::string url;
+        int topRow;
+    };
+
+    void navigate(const std::string& url, bool remember = true, bool preferSaved = false);
+    void follow(const std::string& link);
+    std::string titleOf() const;
+    bool isSaved() const { return !page_.savedFrom.empty(); }
+    std::string savedPathOf() const { return page_.url.substr(7); }  // file://…
+    void show(GeminiPage&& page);
+    void analyse();  // types and links of the lines in memory
+    void applyWindow(GeminiPage&& window);
+    void requestWindow(size_t firstLine);
+    size_t topLine() const;  // the source line (in the whole page) at the top of the screen
+    bool moreBelow() const { return page_.windowed && page_.windowStart + page_.text.lineCount() < page_.totalLines; }
+    bool moreAbove() const { return page_.windowed && page_.windowStart > 0; }
+    void showMessage(const std::string& url, const std::string& gemtext);
+    void layout(Canvas& c);
+    void drawLine(Canvas& c, size_t index, int firstRow, int y, int rows);
+    std::vector<std::string> rowsOf(Canvas& c, size_t index) const;
+    gemini::GemLine lineAt(size_t index) const;
+    int rowsOnScreen() const;
+    void selectLink(int direction);
+    void scrollTo(int row);
+
+    GeminiService& gemini_;
+    GeminiPage page_;
+    std::vector<uint8_t> types_;      // per source line: gemini::LineType
+    std::vector<uint32_t> firstRow_;  // per source line, plus the total at the end
+    std::vector<uint32_t> links_;     // source lines that are links
+    bool layoutDirty_ = true;
+    int topRow_ = 0, hscroll_ = 0;
+    int selected_ = -1;  // into links_
+    int restoreRow_ = -1;  // going back: where that page was scrolled to, applied after layout
+    bool windowLoading_ = false;
+    long keepLine_ = -1;   // a new window: the source line to keep at the top, applied after layout
+    std::vector<Visit> history_;
+    bool loading_ = false;
+    std::string loadingUrl_, status_;
+    uint32_t statusMs_ = 0;
+    bool addressOpen_ = false;
+    LineEditor address_{1024};
+    std::unique_ptr<DialogModel> certDialog_;
+    GeminiPage pendingCert_;
+    std::unique_ptr<DialogModel> deleteDialog_;
+    bool inputOpen_ = false, inputSensitive_ = false;
+    std::string inputPrompt_, inputUrl_;
+    LineEditor input_{1024};
+    std::string reopen_;  // after a refresh: the Saved Page to show again
+};
+
+}  // namespace roro

src/apps/gnss_app.cpp

@@ -0,0 +1,212 @@
+#include "gnss_app.h"
+
+#include <Arduino.h>
+
+#include <cmath>
+#include <cstdio>
+
+#include "geo_format.h"
+#include "ui/canvas.h"
+#include "ui/fonts.h"
+#include "ui/theme.h"
+
+namespace roro {
+
+using namespace gnss;
+
+namespace {
+
+// One colour per constellation, readable in the 8-bit frame buffer.
+uint16_t colorOf(Constellation c) {
+    switch (c) {
+        case Constellation::Gps: return theme::kAccent;
+        case Constellation::Glonass: return 0xF8C8;  // red
+        case Constellation::Galileo: return theme::kMessage;
+        case Constellation::BeiDou: return 0xFEA0;   // yellow
+        case Constellation::Qzss: return 0xC99F;     // violet
+        default: return theme::kText;
+    }
+}
+
+const char* fixLabel(FixType f) { return f == FixType::ThreeD ? "3D Fix" : f == FixType::TwoD ? "2D Fix" : "No Fix"; }
+
+std::string duration(uint32_t ms) {
+    uint32_t s = ms / 1000;
+    char buf[24];
+    if (s < 60) std::snprintf(buf, sizeof buf, "%lu s", (unsigned long)s);
+    else std::snprintf(buf, sizeof buf, "%lu min %02lu s", (unsigned long)(s / 60), (unsigned long)(s % 60));
+    return buf;
+}
+
+}  // namespace
+
+bool GnssApp::onKey(const KeyEvent& e) {
+    if (e.key == Key::Tab) {
+        sky_ = !sky_;
+        requestRedraw();
+        return true;
+    }
+    if (e.key == Key::Char && (e.ch == 'r' || e.ch == 'R')) {  // record a Track, or stop it
+        if (gnss_.tracking()) gnss_.stopTrack();
+        else {
+            refusal_ = gnss_.startTrack(millis());
+            refusalMs_ = millis();
+        }
+        requestRedraw();
+        return true;
+    }
+    return false;  // Back leaves the App
+}
+
+void GnssApp::update(uint32_t nowMs) {
+    if (nowMs - lastDrawMs_ >= 1000) {  // the receiver reports once a second
+        lastDrawMs_ = nowMs;
+        requestRedraw();
+    }
+}
+
+void GnssApp::draw(Canvas& c) {
+    c.setTextDatum(top_left);
+    const auto& area = theme::kContent;
+    if (!gnss_.on()) {
+        c.setFont(&fonts::bold);
+        c.setTextColor(theme::kText);
+        c.drawString("GNSS is off", 4, area.y + 4);
+        c.setFont(&fonts::body);
+        c.setTextColor(theme::kMuted);
+        c.drawString("Settings > GNSS turns it on.", 4, area.y + 22);
+        return;
+    }
+    sky_ ? drawSky(c) : drawPosition(c);
+    c.setFont(&fonts::small);
+    c.setTextColor(theme::kMuted);
+    c.setTextDatum(top_right);
+    c.drawString(sky_ ? "Tab: position" : "Tab: sky", area.w - 3, area.y + area.h - 9);
+    c.setTextDatum(top_left);
+}
+
+void GnssApp::drawPosition(Canvas& c) {
+    const auto& area = theme::kContent;
+    const GnssState& s = gnss_.state();
+    uint32_t now = millis();
+    int used = 0;
+    for (auto& sat : s.satellites) used += sat.used;
+    char line[64];
+
+    c.setFont(&fonts::bold);
+    c.setTextColor(s.fix == FixType::None ? theme::kWarning : theme::kMessage);
+    if (!gnss_.receiving(now)) std::snprintf(line, sizeof line, "No data from the receiver");
+    else if (s.fix == FixType::None)
+        std::snprintf(line, sizeof line, "Searching: %u in view, %s", (unsigned)s.satellites.size(),
+                      duration(now - gnss_.onSinceMs()).c_str());
+    else std::snprintf(line, sizeof line, "%s, %d of %u satellites", fixLabel(s.fix), s.satellitesUsed,
+                       (unsigned)s.satellites.size());
+    c.drawString(line, 4, area.y + 2);
+
+    c.setFont(&fonts::body);
+    int y = area.y + 19;
+    auto row = [&](const char* label, const std::string& value) {
+        c.setTextColor(theme::kMuted);
+        c.drawString(label, 4, y);
+        c.setTextColor(theme::kText);
+        c.drawString(value.c_str(), 64, y);
+        y += theme::kLineHeight;
+    };
+    bool dms = settings_.getBool(Setting::CoordinatesDms);
+    if (s.positionValid) {
+        row("Lat", dms ? formatDms(s.latitude, true) : formatDecimal(s.latitude, true));
+        row("Lon", dms ? formatDms(s.longitude, false) : formatDecimal(s.longitude, false));
+        row("Locator", maidenhead(s.latitude, s.longitude));
+        std::snprintf(line, sizeof line, s.altitudeValid ? "%.0f m" : "-", s.altitudeM);
+        row("Altitude", line);
+        if (s.courseValid && s.speedKmh >= 1.0f)
+            std::snprintf(line, sizeof line, "%.1f km/h, %.0f\xC2\xB0", s.speedKmh, s.courseDeg);
+        else std::snprintf(line, sizeof line, "%.1f km/h", s.speedKmh);
+        row("Speed", line);
+    } else {
+        row("Lat", "-");
+        row("Lon", "-");
+        y += theme::kLineHeight * 3;
+    }
+    std::snprintf(line, sizeof line, "%.1f", s.hdop);
+    row("HDOP", s.fix == FixType::None ? "-" : line);
+    if (s.timeValid) std::snprintf(line, sizeof line, "%02d:%02d:%02d UTC", s.hour, s.minute, s.second);
+    row("Time", s.timeValid ? line : "-");
+
+    // The Track line, at the bottom left.
+    c.setFont(&fonts::small);
+    if (gnss_.tracking()) {
+        c.setTextColor(theme::kWarning);
+        std::snprintf(line, sizeof line, "REC %d point%s, %s  r: stop", gnss_.trackPoints(),
+                      gnss_.trackPoints() == 1 ? "" : "s", duration(now - gnss_.trackStartMs()).c_str());
+    } else if (!refusal_.empty() && now - refusalMs_ < 4000) {
+        c.setTextColor(theme::kWarning);
+        std::snprintf(line, sizeof line, "%s", refusal_.c_str());
+    } else {
+        c.setTextColor(theme::kMuted);
+        std::snprintf(line, sizeof line, "r: record a Track");
+    }
+    c.drawString(line, 4, area.y + area.h - 9);
+}
+
+void GnssApp::drawSky(Canvas& c) {
+    const auto& area = theme::kContent;
+    const GnssState& s = gnss_.state();
+    const int radius = (area.h - 6) / 2, cx = 4 + radius, cy = area.y + area.h / 2;
+
+    // The sky from above: horizon, 30° and 60° elevation rings, north up.
+    c.drawCircle(cx, cy, radius, theme::kMuted);
+    c.drawCircle(cx, cy, radius * 2 / 3, 0x4208);
+    c.drawCircle(cx, cy, radius / 3, 0x4208);
+    c.drawFastHLine(cx - radius, cy, 2 * radius, 0x4208);
+    c.drawFastVLine(cx, cy - radius, 2 * radius, 0x4208);
+    c.setFont(&fonts::small);
+    c.setTextColor(theme::kMuted);
+    c.setTextDatum(middle_center);
+    auto compass = [&](const char* letter, int x, int y) {
+        c.fillRect(x - 3, y - 4, 7, 9, theme::kBackground);  // off the lines, so it reads
+        c.drawString(letter, x, y);
+    };
+    compass("N", cx, cy - radius + 5);
+    compass("S", cx, cy + radius - 4);
+    compass("E", cx + radius - 4, cy);
+    compass("W", cx - radius + 4, cy);
+    c.setTextDatum(top_left);
+
+    int inView[8] = {}, usedBy[8] = {};
+    for (auto& sat : s.satellites) {
+        int k = static_cast<int>(sat.system);
+        inView[k]++;
+        usedBy[k] += sat.used;
+        SkyPoint p = skyPosition(sat.azimuth, sat.elevation, cx, cy, radius - 3);
+        uint16_t color = colorOf(sat.system);
+        if (sat.used) c.fillCircle(p.x, p.y, 3, color);
+        else c.drawCircle(p.x, p.y, 3, sat.snr < 0 ? theme::kMuted : color);
+    }
+
+    // Legend: used / in view per constellation, then the Fix.
+    int x = cx + radius + 12, y = area.y + 4;
+    c.setFont(&fonts::body);
+    for (int k = 1; k < 7; k++) {
+        if (!inView[k]) continue;
+        auto system = static_cast<Constellation>(k);
+        c.fillCircle(x + 3, y + 6, 3, colorOf(system));
+        char line[32];
+        std::snprintf(line, sizeof line, "%-8s%d/%d", constellationName(system), usedBy[k], inView[k]);
+        c.setTextColor(theme::kText);
+        c.drawString(line, x + 10, y);
+        y += theme::kLineHeight;
+    }
+    if (s.satellites.empty()) {
+        c.setTextColor(theme::kMuted);
+        c.drawString("No satellites", x, y);
+        y += theme::kLineHeight;
+    }
+    c.setTextColor(s.fix == FixType::None ? theme::kWarning : theme::kMessage);
+    c.drawString(fixLabel(s.fix), x, y + 4);
+    c.setFont(&fonts::small);
+    c.setTextColor(theme::kMuted);
+    c.drawString("filled: in use", x, area.y + area.h - 20);
+}
+
+}  // namespace roro

src/apps/gnss_app.h

@@ -0,0 +1,33 @@
+#pragma once
+
+#include <string>
+
+#include "app.h"
+#include "services/gnss_service.h"
+#include "settings.h"
+
+namespace roro {
+
+// GNSS (see docs/milestones/M2.md, Q59): the Position view, and the Sky view with every satellite
+// in view placed by direction and elevation. Tab switches between them.
+class GnssApp : public App {
+   public:
+    GnssApp(GnssService& gnss, const Settings& settings) : gnss_(gnss), settings_(settings) {}
+    void onEnter() override { requestRedraw(); }
+    bool onKey(const KeyEvent& e) override;
+    void update(uint32_t nowMs) override;
+    void draw(Canvas& c) override;
+
+   private:
+    void drawPosition(Canvas& c);
+    void drawSky(Canvas& c);
+
+    GnssService& gnss_;
+    const Settings& settings_;
+    bool sky_ = false;
+    uint32_t lastDrawMs_ = 0;
+    std::string refusal_;  // why a Track couldn't start, shown for a few seconds
+    uint32_t refusalMs_ = 0;
+};
+
+}  // namespace roro

src/apps/irc_app.cpp

@@ -42,7 +42,7 @@ std::string lowered(std::string s) {
 void IrcApp::onEnter() {
     page_ = Page::Chat;
     editing_ = false;
-    irc_.connect();
+    if (!irc_.stoppedByUser()) irc_.connect();  // stopped by hand: stay stopped, typing reconnects
     view(current_);
 }
 

src/apps/settings_app.cpp

@@ -34,6 +34,9 @@ bool SettingsApp::onKey(const KeyEvent& e) {
         case Page::Wifi:
             if (!wifiPage_.onKey(e)) page_ = Page::Menu;
             return true;
+        case Page::Firmware:
+            if (!firmwarePage_.onKey(e)) page_ = Page::Menu;
+            return true;
     }
     return false;
 }
@@ -75,6 +78,10 @@ bool SettingsApp::onMenuKey(const KeyEvent& e) {
                     page_ = Page::Wifi;
                     wifiPage_.enter();
                     break;
+                case Row::Firmware:
+                    page_ = Page::Firmware;
+                    firmwarePage_.enter();
+                    break;
                 default: page_ = Page::About; break;
             }
             break;
@@ -124,7 +131,8 @@ bool SettingsApp::onAboutKey(const KeyEvent& e) {
 
 void SettingsApp::update(uint32_t nowMs) {
     // Live values on Storage and About.
-    bool live = page_ == Page::Storage || page_ == Page::About || (page_ == Page::Wifi && wifiPage_.live());
+    bool live = page_ == Page::Storage || page_ == Page::About || page_ == Page::Firmware ||
+                (page_ == Page::Wifi && wifiPage_.live());
     if (live && nowMs - lastRefreshMs_ >= 500) {
         lastRefreshMs_ = nowMs;
         requestRedraw();
@@ -183,6 +191,7 @@ void SettingsApp::draw(Canvas& c) {
         case Page::Storage: storagePage_.draw(c); break;
         case Page::About: widgets::textLines(c, aboutLines(), 0, area); break;
         case Page::Wifi: wifiPage_.draw(c); break;
+        case Page::Firmware: firmwarePage_.draw(c); break;
     }
 }
 

src/apps/settings_app.h

@@ -13,6 +13,7 @@
 #include "services/battery_service.h"
 #include "services/clock_service.h"
 #include "services/storage_service.h"
+#include "apps/firmware_page.h"
 #include "apps/storage_page.h"
 #include "apps/wifi_settings_page.h"
 #include "settings_menu.h"
@@ -29,6 +30,7 @@ struct SettingsAppDeps {
     ClockService& clock;
     WifiService& wifi;
     SavedNetworks& savedNetworks;
+    UpdateService& update;
 };
 
 // Settings: every user-facing setting, plus the Storage and About pages.
@@ -38,7 +40,8 @@ class SettingsApp : public App {
         : d_(deps),
           menu_(deps.settings),
           wifiPage_(deps.settings, deps.savedNetworks, deps.wifi, deps.bus),
-          storagePage_(deps.storage, deps.clock, deps.bus) {}
+          storagePage_(deps.storage, deps.clock, deps.bus),
+          firmwarePage_(deps.update, deps.wifi, deps.storage) {}
     void onEnter() override;
     bool onKey(const KeyEvent& e) override;
     void update(uint32_t nowMs) override;
@@ -48,7 +51,7 @@ class SettingsApp : public App {
     void draw(Canvas& c) override;
 
    private:
-    enum class Page { Menu, Text, Choice, Storage, About, Wifi };
+    enum class Page { Menu, Text, Choice, Storage, About, Wifi, Firmware };
 
     bool onMenuKey(const KeyEvent& e);
     bool onTextKey(const KeyEvent& e);
@@ -61,6 +64,7 @@ class SettingsApp : public App {
     SettingsMenu menu_;
     WifiSettingsPage wifiPage_;
     StoragePage storagePage_;
+    FirmwarePage firmwarePage_;
     Page page_ = Page::Menu;
     ListModel list_{theme::kContent.h / theme::kLineHeight};
     ListModel choices_{theme::kContent.h / theme::kLineHeight};

src/main.cpp

@@ -2,24 +2,39 @@
 #include <M5Cardputer.h>
 #include <SD.h>
 
+
+#include <atomic>
+#include <memory>
+
 #include "app_manager.h"
 #include "apps/demo_app.h"
+#include "apps/gemini_app.h"
+#include "apps/gnss_app.h"
 #include "apps/irc_app.h"
 #include "apps/launcher_app.h"
 #include "apps/settings_app.h"
 #include "apps/wifi_tools_app.h"
 #include "apps/setup_app.h"
 #include "event_bus.h"
+#include "file_receiver.h"
 #include "key_mapper.h"
+#include "platform/console.h"
+#include "platform/crash_report.h"
 #include "platform/nvs_store.h"
+#include "platform/system_info.h"
 #include "service_manager.h"
 #include "platform/identity.h"
 #include "services/battery_service.h"
 #include "services/irc_service.h"
 #include "services/clock_service.h"
+#include "services/debug_console.h"
+#include "services/gemini_service.h"
+#include "services/gnss_service.h"
 #include "services/power_service.h"
 #include "services/storage_service.h"
+#include "services/update_service.h"
 #include "services/wifi_service.h"
+#include "safe_mode.h"
 #include "settings.h"
 #include "storage_paths.h"
 #include "ui/notifier.h"
@@ -40,12 +55,19 @@ static BatteryService* battery;
 static StorageService* storageService;
 static PowerService* power;
 static ClockService* clockService;
+static GnssService* gnssService;
+static GeminiService* geminiService;
 static SavedNetworks* savedNetworks;
 static WifiService* wifi;
 static IrcService* irc;
+static UpdateService* update;
+#ifdef RORO_DEBUG
+static DebugConsole* debugConsole;
+#endif
 static Notifier* notifier;
 static LauncherApp launcher;
 static AppManager* apps;
+static bool safeMode = false;  // see SafeMode: only what it takes to be fixed over the air
 
 static RawKeys readKeys() {
     auto state = M5Cardputer.Keyboard.keysState();
@@ -73,6 +95,15 @@ static StatusInfo currentStatus() {
     s.sdLevel = storageState.level;
     s.compose = keyMapper.pendingCompose();
     s.unread = irc->totalUnread();
+    if (gnssService && gnssService->on()) {
+        const auto& g = gnssService->state();
+        bool fresh = gnssService->receiving(millis());
+        s.gnss = !fresh || g.fix == gnss::FixType::None ? StatusInfo::Gnss::Searching
+                 : g.fix == gnss::FixType::TwoD        ? StatusInfo::Gnss::TwoD
+                                                       : StatusInfo::Gnss::ThreeD;
+        s.gnssSatellites = g.satellitesUsed;
+        s.tracking = gnssService->tracking();
+    }
     using WifiState = WifiController::State;
     switch (wifi->state()) {
         case WifiState::Connected: {
@@ -88,51 +119,118 @@ static StatusInfo currentStatus() {
     return s;
 }
 
+// Arduino-ESP32 marks a new image valid before setup() unless this returns true. Probation
+// (UpdateService::tick) decides instead, and an unconfirmed image stays PENDING_VERIFY.
+extern "C" bool verifyRollbackLater() { return true; }  // C linkage, or the weak default wins
+
+// The main loop's stack: Arduino's default is 8 KB; the measured peak is 3 KB (M2).
+size_t getArduinoLoopTaskStackSize() { return 6144; }
+
+static void setupSafeMode(int crashes);
+
 void setup() {
+    nvs.begin();
+    UpdateService::bootGuard(nvs);  // first: before anything that could crash on new firmware
+    int crashes = crash_report::noteBoot(nvs);
+    safeMode = SafeMode::active(crashes);
+    Serial.setRxBufferSize(2 * FileReceiver::kChunk);  // before the port opens; sd put sends 1 chunk at a time
+    Serial.setTxBufferSize(1024);  // the console skips Serial when it's full: room for a burst like `tasks`
+
     auto cfg = M5.config();
     M5Cardputer.begin(cfg, true);
     M5Cardputer.Display.setRotation(1);
     Serial.begin(115200);
 
-    nvs.begin();
     settings.load();
+    if (safeMode) return setupSafeMode(crashes);
 
     battery = new BatteryService(bus);
     storageService = new StorageService(bus);
     power = new PowerService(settings);
     clockService = new ClockService(settings, bus);
+    geminiService = new GeminiService(nvs, *storageService, *clockService, bus);
+    gnssService = new GnssService(settings, *clockService, *storageService, bus);
     savedNetworks = new SavedNetworks(nvs);
     savedNetworks->load();
     wifi = new WifiService(settings, *savedNetworks, *clockService);
+    update = new UpdateService(nvs, *wifi, *savedNetworks, *storageService, bus, settings);
     irc = new IrcService(nvs, "roro_" + identity::defaultShortName(), *wifi, *storageService, *clockService, bus);
     notifier = new Notifier(bus, settings);
     notifier->onShow = [](uint32_t now, uint32_t until) { power->onNotification(now, until); };
     services.add(*power);
     services.add(*clockService);
     services.add(*battery);
+    services.add(*gnssService);
     services.add(*storageService);
     services.add(*wifi);
     services.add(*irc);
+    services.add(*update);
+#ifdef RORO_DEBUG
+    debugConsole = new DebugConsole(*wifi, *storageService);
+    services.add(*debugConsole);
+#endif
 
     apps = new AppManager(launcher);
     launcher.setManager(*apps);
     apps->registerApp({"irc", "IRC", false, new IrcApp(*irc, *clockService, bus)});
     apps->registerApp({"wifi-tools", "Wi-Fi Tools", false, new WifiToolsApp(*wifi, *storageService, *clockService)});
+    apps->registerApp({"gnss", "GNSS", false, new GnssApp(*gnssService, settings)});
+    apps->registerApp({"gemini", "Gemini", false, new GeminiApp(*geminiService)});
     apps->registerApp({"settings", "Settings", false,
-                       new SettingsApp({settings, bus, *apps, *battery, *storageService, *clockService, *wifi, *savedNetworks})});
+                       new SettingsApp({settings, bus, *apps, *battery, *storageService, *clockService, *wifi, *savedNetworks, *update})});
     apps->registerApp({"demo", "Widget demo", true, new DemoApp(bus)});
     apps->registerApp({"setup", "Setup", true, new SetupApp(settings, *apps)});
 
-    bus.subscribe(EventType::Notification, [](const Event& e) { Serial.printf("notification: %s\n", e.text); });
+    bus.subscribe(EventType::Notification, [](const Event& e) { console.printf("notification: %s\n", e.text); });
 
-    if (!screen.begin()) Serial.println("frame buffer allocation failed");
+    if (!screen.begin()) console.println("frame buffer allocation failed");
+#ifdef RORO_DEBUG
+    debugConsole->setFrame(screen.canvas());  // for `screenshot`
+#endif
     services.startAll(millis());
     apps->begin();
     if (!settings.getBool(Setting::SetupDone)) apps->openModal("setup");
-    Serial.printf("%s %s ready, free heap %u\n", kProductName, versionString(), ESP.getFreeHeap());
+    console.printf("%s %s ready, free heap %u, last start: %s\n", kProductName, versionString(), ESP.getFreeHeap(),
+                   system_info::resetReason());
+    if (system_info::resetWasCrash()) {
+        crash_report::print(console, nvs);
+        bus.publish(Event::withText(EventType::Notification, crash_report::headline().c_str(),
+                                    static_cast<int32_t>(NotificationLevel::Warning)));
+    }
+    // A main loop stuck for 5 s panics (and leaves a core dump) instead of hanging forever: Arduino
+    // only watches the idle task on core 0, and the loop runs on core 1.
+    enableLoopWDT();
 }
 
-// Dev aid: serial commands to drive the UI without the keyboard.
+// Safe Mode: Wi-Fi, the clock, Firmware Updates and (in a Debug Build) the Debug Console. No Apps,
+// no IRC, no SD card: whatever crashed three times in a row is most likely among them.
+static void setupSafeMode(int crashes) {
+    clockService = new ClockService(settings, bus);
+    savedNetworks = new SavedNetworks(nvs);
+    savedNetworks->load();
+    wifi = new WifiService(settings, *savedNetworks, *clockService);
+    storageService = new StorageService(bus);  // never started: no card access
+    update = new UpdateService(nvs, *wifi, *savedNetworks, *storageService, bus, settings);
+    services.add(*clockService);
+    services.add(*wifi);
+    services.add(*update);
+#ifdef RORO_DEBUG
+    debugConsole = new DebugConsole(*wifi, *storageService);
+    services.add(*debugConsole);
+#endif
+    bus.subscribe(EventType::Notification, [](const Event& e) { console.printf("notification: %s\n", e.text); });
+    screen.begin();
+#ifdef RORO_DEBUG
+    debugConsole->setFrame(screen.canvas());
+#endif
+    services.startAll(millis());
+    console.printf("%s %s in SAFE MODE: %d crash restarts in a row. Only Wi-Fi and Firmware Updates run.\n",
+                   kProductName, versionString(), crashes);
+    crash_report::print(console, nvs);
+    enableLoopWDT();
+}
+
+// Dev aid: commands to drive the UI without the keyboard, from the serial port or the Debug Console.
 static bool listingWanted = false;
 
 static void printListingWhenReady() {
@@ -142,29 +240,204 @@ static void printListingWhenReady() {
     for (size_t i = 0; i < listing.size(); i++) {
         uint64_t bytes = 0;
         for (auto& f : listing[i]) bytes += f.bytes;
-        Serial.printf("sd list: %-20s %u files, %s\n", kCleanupCategories[i].label, (unsigned)listing[i].size(),
+        console.printf("sd list: %-20s %u files, %s\n", kCleanupCategories[i].label, (unsigned)listing[i].size(),
                        formatBytes(bytes).c_str());
-        for (auto& f : listing[i]) Serial.printf("  %s (%u B)\n", f.path.c_str(), (unsigned)f.bytes);
+        for (auto& f : listing[i]) console.printf("  %s (%u B)\n", f.path.c_str(), (unsigned)f.bytes);
     }
 }
 
-static void serialCommands() {
+// sd put: a file sent over serial by scripts/sd_put.py. The main loop reads the bytes; every card
-    static String line;
+// access runs as a Storage Service job, which reports back through uploadResult.
-    while (Serial.available()) {
+static FileReceiver upload;
-        char c = Serial.read();
+static std::atomic<int> uploadResult{-1};  // set by a job: 1 ok, 0 failed; -1 nothing new
-        if (c != '\n') {
+static bool uploadJobRunning = false;
-            line += c;
+
-            continue;
+static void uploadJob(std::function<bool()> job) {
+    uploadJobRunning = true;
+    storageService->runJob([job]() { uploadResult = job() ? 1 : 0; });
+}
+
+static void startUpload(const String& args) {
+    if (upload.active() || uploadJobRunning) return (void)Serial.println("sd put: error busy");
+    std::string error = upload.begin(args.c_str(), millis());
+    StorageState card = storageService->state();
+    if (error.empty() && !card.present) error = "no SD card";
+    if (error.empty() && card.totalBytes - card.usedBytes < upload.size() + 64 * 1024) error = "not enough space";
+    if (!error.empty()) {
+        upload.reset();
+        return (void)Serial.printf("sd put: error %s\n", error.c_str());
     }
+    std::string part = upload.partPath();
+    uploadJob([part]() {
+        for (size_t slash = part.find('/', 1); slash != std::string::npos; slash = part.find('/', slash + 1)) {
+            std::string dir = part.substr(0, slash);
+            if (!SD.exists(dir.c_str()) && !SD.mkdir(dir.c_str())) return false;
+        }
+        if (SD.exists(part.c_str())) SD.remove(part.c_str());
+        return true;
+    });
+}
+
+static void readUploadBytes() {
+    uint8_t buf[256];
+    size_t want;
+    while (!uploadJobRunning && (want = std::min(upload.wanted(), sizeof buf)) > 0 && Serial.available() > 0) {
+        size_t n = Serial.read(buf, std::min<size_t>(want, Serial.available()));
+        upload.feed(buf, n, millis());
+    }
+}
+
+static void uploadStep() {
+    using S = FileReceiver::State;
+    uint32_t now = millis();
+    int result = uploadResult.exchange(-1);
+    if (result >= 0) {
+        uploadJobRunning = false;
+        bool ok = result == 1;
+        switch (upload.state()) {
+            case S::Receiving:  // the folder job from startUpload: the sender may start
+                if (ok) Serial.printf("sd put: ready %u\n", (unsigned)FileReceiver::kChunk);
+                else {
+                    upload.reset();
+                    return (void)Serial.println("sd put: error card not writable");
+                }
+                break;
+            case S::Writing:
+                upload.chunkWritten(ok, now);
+                if (upload.state() == S::Receiving) Serial.printf("sd put: ok %u\n", (unsigned)upload.received());
+                break;
+            case S::Finishing: upload.finished(ok); break;
+            default: break;  // a job that finished after the transfer failed
+        }
+    }
+    if (!upload.active()) return;
+    upload.tick(now);
+    std::string path = upload.path(), part = upload.partPath();
+    if (upload.state() == S::Failed) {
+        // Reported even if a job never came back (no card: the storage task drops it).
+        Serial.printf("sd put: error %s\n", upload.error().c_str());
+        storageService->runJob([part]() { SD.remove(part.c_str()); });
+        upload.reset();
+        uploadJobRunning = false;
+        return;
+    }
+    if (uploadJobRunning) return;
+    if (upload.state() == S::Writing) {
+        auto chunk = std::make_shared<std::vector<uint8_t>>(upload.chunk());
+        uploadJob([chunk, part]() {
+            File f = SD.open(part.c_str(), FILE_APPEND);
+            bool ok = f && f.write(chunk->data(), chunk->size()) == chunk->size();
+            if (f) f.close();
+            return ok;
+        });
+    } else if (upload.state() == S::Finishing) {
+        uploadJob([path, part]() {
+            if (SD.exists(path.c_str())) SD.remove(path.c_str());
+            return SD.rename(part.c_str(), path.c_str());
+        });
+    } else if (upload.state() == S::Done) {
+        Serial.printf("sd put: done %s %u B\n", path.c_str(), (unsigned)upload.size());
+        upload.reset();
+    }
+}
+
+static const char* const kHelp =
+    "info              firmware, uptime, memory, Wi-Fi, app slots\n"
+    "tasks             FreeRTOS tasks: state, priority, free stack, CPU\n"
+    "reboot            restart\n"
+    "boot other        restart into the other app slot (manual Rollback)\n"
+    "log level <0-5>   ESP-IDF log level (0 none ... 5 verbose)\n"
+    "gnss status | gnss restart | gnss track start|stop | gnss nmea on|off | gnss send <sentence without $ and checksum>\n"
+    "crash             the last crash: firmware, reason, task, backtrace\n"
+    "coredump erase    forget the core dump in flash\n"
+    "key <name|char>   press a key: up down left right select back home del tab space, or one character\n"
+    "wifi status | wifi add <ssid><TAB><password>\n"
+    "gemini get <url>  fetch a Gemini page and report header, size, certificate, heap\n"
+    "irc start | irc stop | irc dump | irc say <buffer> <text>\n"
+    "ls [folder] | rm <path> | install <path.ota> (Update from SD)\n"
+    "sd list | cat <path> | log <text> | burst | sound on|off | short | normal\n"
+#ifdef RORO_DEBUG
+    "crash abort|wdt   crash on purpose (to test crash reports and Safe Mode)\n"
+    "coredump get      (Debug Console only) send the raw core dump: use scripts/rdbg.py coredump\n"
+    "reset             (Debug Console only) restart at once, even if the main loop is stuck\n"
+    "get <path> | put <path> <size> <sha256> | screenshot   (Debug Console only) binary, see rdbg.py\n"
+    "quit              close the Debug Console connection\n"
+#endif
+    ;
+
+// Commands that only touch what Safe Mode starts.
+static bool safeModeCommand(const String& line) {
+    return line == "help" || line == "info" || line == "tasks" || line == "reboot" || line == "boot other" ||
+           line.startsWith("log level ") || line.startsWith("crash") || line.startsWith("coredump") ||
+           line == "wifi status" || line.startsWith("wifi add ");
+}
+
+static void runCommand(String line) {
     line.trim();
+    if (line.isEmpty()) return;
+    if (safeMode && !safeModeCommand(line)) return (void)console.println("not available in Safe Mode");
+    if (line == "help") console.print(kHelp);
+    if (line == "info") {
+        system_info::printSystem(console);
+        console.printf("wifi: %s, ip %s, rssi %d | sd: %s\n", wifi->ssid().c_str(), wifi->ip().c_str(), wifi->rssi(),
+                       storageService->state().present ? "present" : "none");
+        console.printf("update: %s\n", update->onProbation() ? "on probation" : "confirmed");
+        system_info::printSlots(console, nvs);
+    }
+    if (line == "tasks") system_info::printTasks(console);
+    if (line == "reboot") {
+        console.println("restarting");
+        delay(300);
+        ESP.restart();
+    }
+    if (line == "boot other") console.printf("boot other: %s\n", system_info::bootOtherSlot());
+    if (line.startsWith("log level ")) {
+        int level = line.substring(10).toInt();
+        esp_log_level_set("*", static_cast<esp_log_level_t>(constrain(level, 0, 5)));
+        console.printf("log level: %d\n", constrain(level, 0, 5));
+    }
+    if (line == "ls" || line.startsWith("ls ") || line.startsWith("rm ")) {
+        if (!storageService->state().present) return (void)console.println("sd: no card");
+        bool list = !line.startsWith("rm ");
+        std::string path = line.length() > 3 ? line.substring(3).c_str() : "/";
+        storageService->runJob([list, path]() {  // card access stays on the storage task
+            if (!list) return (void)console.printf("rm: %s %s\n", path.c_str(), SD.remove(path.c_str()) ? "removed" : "failed");
+            File dir = SD.open(path.c_str());
+            if (!dir || !dir.isDirectory()) return (void)console.printf("ls: %s is not a folder\n", path.c_str());
+            for (File f = dir.openNextFile(); f; f = dir.openNextFile())
+                console.printf("%10u  %s%s\n", f.isDirectory() ? 0u : (unsigned)f.size(), f.name(), f.isDirectory() ? "/" : "");
+            console.printf("ls: end of %s\n", path.c_str());
+        });
+    }
+    if (line.startsWith("install ")) update->installFromSd(line.substring(8).c_str());  // Update from SD
+    if (line == "gnss status" && gnssService) gnssService->printStatus(console, millis());
+    if ((line == "gnss nmea on" || line == "gnss nmea off") && gnssService) gnssService->setEcho(line.endsWith("on"));
+    if (line == "gnss restart" && gnssService) gnssService->restart(millis());
+    if (line == "gnss track start" && gnssService) {
+        std::string why = gnssService->startTrack(millis());
+        console.printf("gnss track: %s\n", why.empty() ? "recording" : why.c_str());
+    }
+    if (line == "gnss track stop" && gnssService) gnssService->stopTrack();
+    if (line.startsWith("gnss send ") && gnssService)  // the checksum is added
+        console.println(gnssService->send(line.substring(10).c_str()) ? "gnss: sent" : "gnss: off");
+    if (line == "crash") crash_report::print(console, nvs);
+    if (line == "coredump erase") console.println(crash_report::erase() ? "coredump: erased" : "coredump: nothing to erase");
+#ifdef RORO_DEBUG
+    if (line == "crash abort") abort();
+    if (line == "crash wdt")
+        for (;;) {}  // the main loop never yields: the task watchdog fires
+#endif
     if (line == "burst")
         for (int i = 1; i <= 5; i++)
             bus.publish(Event::withText(EventType::Notification, ("Burst " + String(i)).c_str(), 0));
-        if (line.startsWith("key ")) {  // key up|down|left|right|select|back|home
+    if (line.startsWith("key ")) {  // key up|down|left|right|select|back|home|del|tab
         String k = line.substring(4);
         Key key = k == "up" ? Key::Up : k == "down" ? Key::Down : k == "left" ? Key::Left
-                    : k == "right" ? Key::Right : k == "back" ? Key::Back : k == "home" ? Key::Home : Key::Select;
+                : k == "right" ? Key::Right : k == "back" ? Key::Back : k == "home" ? Key::Home
-            KeyEvent ev = k.length() == 1 && k[0] > ' ' ? KeyEvent::character((unsigned char)k[0]) : KeyEvent::of(key);
+                : k == "del" ? Key::Delete : k == "tab" ? Key::Tab : Key::Select;
+        KeyEvent ev = k == "space"                       ? KeyEvent::character(' ')
+                      : k.length() == 1 && k[0] > ' ' ? KeyEvent::character((unsigned char)k[0])
+                                                      : KeyEvent::of(key);
         if (!power->onKey(millis())) apps->handleKey(ev);
     }
     if (line.startsWith("wifi add ")) {  // wifi add <ssid>\t<password>: credentials never touch the repo
@@ -172,31 +445,40 @@ static void serialCommands() {
         std::string ssid = (tab > 0 ? line.substring(9, tab) : line.substring(9)).c_str();
         std::string pass = tab > 0 ? line.substring(tab + 1).c_str() : "";
         std::string error = savedNetworks->add(ssid, pass);
-            Serial.printf("wifi add: %s\n", error.empty() ? "ok" : error.c_str());
+        console.printf("wifi add: %s\n", error.empty() ? "ok" : error.c_str());
         wifi->savedNetworksChanged();
     }
-        if (line.startsWith("log ")) {  // appends to a test IRC Log
+    if (line.startsWith("log ") && !line.startsWith("log level ")) {  // appends to a test IRC Log
         std::string path = storage::dailyLogPath({"irc", "dev", "#test"}, clockService->localDate());
         storageService->appendLine(path, clockService->displayTime() + " " + line.substring(4).c_str());
-            Serial.printf("log: queued to %s\n", path.c_str());
+        console.printf("log: queued to %s\n", path.c_str());
     }
     if (line.startsWith("cat ")) {
         std::string path = line.substring(4).c_str();
         File f = SD.open(path.c_str());
-            if (!f) Serial.printf("cat: cannot open %s\n", path.c_str());
+        if (!f) console.printf("cat: cannot open %s\n", path.c_str());
         else {
-                Serial.printf("--- %s (%u B) ---\n", path.c_str(), (unsigned)f.size());
+            console.printf("--- %s (%u B) ---\n", path.c_str(), (unsigned)f.size());
             int shown = 0;
-                while (f.available() && shown < 1200) { Serial.write(f.read()); shown++; }
+            while (f.available() && shown < 1200) { console.write(f.read()); shown++; }
-                Serial.println("\n--- end ---");
+            console.println("\n--- end ---");
             f.close();
         }
     }
+    if (line.startsWith("sd put ")) startUpload(line.substring(7));  // then raw bytes: see uploadStep()
     if (line == "sd list") {
         storageService->requestListing();
         listingWanted = true;
     }
+    if (line.startsWith("gemini trust ")) {  // gemini trust <host> <port> <sha256>: accept a changed certificate
+        char host[96] = "", fp[80] = "";
+        int port = 1965;
+        if (geminiService && sscanf(line.substring(13).c_str(), "%95s %d %79s", host, &port, fp) == 3) geminiService->trust(host, port, fp);
+    }
+    if (line.startsWith("gemini get "))
+        if (!geminiService || !geminiService->fetchToConsole(line.substring(11).c_str())) console.println("gemini: busy, or unavailable in Safe Mode");
     if (line == "irc start") irc->connect();
+    if (line == "irc stop") irc->disconnect();
     if (line.startsWith("irc say ")) {  // irc say <buffer index> <text>
         String rest = line.substring(8);
         int space = rest.indexOf(' ');
@@ -205,26 +487,27 @@ static void serialCommands() {
         irc->withSession([&](IrcSession& s) { s.input(b, text, clockService->utcNow()); });
     }
     if (line == "irc dump") {
-            Serial.printf("irc: status %d, unread %d, heap %u min %u\n", (int)irc->status(), irc->totalUnread(),
+        console.printf("irc: status %d, unread %d, heap %u min %u\n", (int)irc->status(), irc->totalUnread(),
                        ESP.getFreeHeap(), ESP.getMinFreeHeap());
         IrcConfig c = irc->draftConfig();  // which login is configured, never the secrets
-            Serial.printf("irc: nick %s, sasl %s, nickserv %s, autojoin %u channels\n", c.nick.c_str(),
+        console.printf("irc: nick %s, sasl %s, nickserv %s, autojoin %u channels\n", c.nick.c_str(),
                        c.saslUser.empty() || c.saslPassword.empty() ? "off" : "on",
                        c.nickservPassword.empty() ? "off" : "on", (unsigned)c.autojoin.size());
         irc->withSession([](IrcSession& s) {
             for (int i = 0; i < s.bufferCount(); i++) {
                 const auto& b = s.buffer(i);
-                    Serial.printf("irc buffer %d %s unread %d%s\n", i, b.name.c_str(), b.unread, b.joined ? " joined" : "");
+                console.printf("irc buffer %d %s unread %d%s\n", i, b.name.c_str(), b.unread, b.joined ? " joined" : "");
                 size_t from = 0;
                 for (size_t j = from; j < b.lines.size(); j++)
-                        Serial.printf("   <%s> %s\n", b.lines[j].nick.c_str(), b.lines[j].text.c_str());
+                    console.printf("   <%s> %s\n", b.lines[j].nick.c_str(), b.lines[j].text.c_str());
             }
         });
     }
     if (line == "wifi status")
-            Serial.printf("wifi: state %d ssid '%s' rssi %d clock %s heap %u min %u\n", (int)wifi->state(),
+        console.printf("wifi: state %d ssid '%s' rssi %d ip %s clock %s heap %u min %u | fw %s%s\n",
-                          wifi->ssid().c_str(), wifi->rssi(), clockService->displayTime().c_str(), ESP.getFreeHeap(),
+                       (int)wifi->state(), wifi->ssid().c_str(), wifi->rssi(), wifi->ip().c_str(),
-                          ESP.getMinFreeHeap());
+                       clockService->displayTime().c_str(), ESP.getFreeHeap(), ESP.getMinFreeHeap(), versionString(),
+                       update->onProbation() ? " (on probation)" : "");
     if (line == "sound off") settings.setBool(Setting::Sound, false);
     if (line == "sound on") settings.setBool(Setting::Sound, true);
     if (line == "short") {
@@ -235,16 +518,76 @@ static void serialCommands() {
         settings.setInt(Setting::OffTimeoutS, 60);
         settings.setInt(Setting::DimTimeoutS, 30);
     }
+}
+
+static void serialCommands() {
+    if (upload.active()) return readUploadBytes();  // raw file bytes, not commands
+    static String line;
+    while (Serial.available()) {
+        char c = Serial.read();
+        if (c != '\n') {
+            line += c;
+            continue;
+        }
+        runCommand(line);
         line = "";
     }
 }
 
+static void remoteCommands() {
+#ifdef RORO_DEBUG
+    for (std::string remote; debugConsole->takeCommand(remote);) {
+        console.printf("> %s\n", remote.c_str());  // so the transcript reads the same on both ends
+        runCommand(remote.c_str());
+    }
+#endif
+}
+
+// After a minute up, the crash streak is over (SafeMode counts starts that crash in a row).
+static void noteStableOnce(uint32_t now) {
+    static bool noted = false;
+    if (noted || now < SafeMode::kStableAfterMs) return;
+    noted = true;
+    crash_report::noteStable(nvs);
+}
+
+static void loopSafeMode() {
+    uint32_t now = millis();
+    serialCommands();
+    remoteCommands();
+    services.tick(now);
+    bus.dispatch();
+    noteStableOnce(now);
+    if (update->phase() == UpdateService::Phase::Installed) {
+        screen.renderUpdate("Restarting", "into " + update->incomingVersion(), -1);
+        delay(800);
+        ESP.restart();
+    }
+    static uint32_t lastDraw = 0;
+    if (update->phase() == UpdateService::Phase::Receiving) {
+        screen.renderUpdate("Firmware update", "Receiving " + update->incomingVersion(), update->percent());
+    } else if (now - lastDraw > 2000 || !lastDraw) {
+        lastDraw = now;
+        bool up = wifi->state() == WifiController::State::Connected;
+        screen.renderUpdate("Safe Mode", up ? "Updates: " + wifi->ip() + ":3232" : "Waiting for Wi-Fi", -1);
+    }
+    delay(10);
+}
+
 void loop() {
+    if (safeMode) return loopSafeMode();
+#ifdef RORO_TEST_CRASH
+    // Test builds only (never in a release): crash during Probation to exercise Rollback.
+    if (millis() > 5000) abort();
+#endif
     static StatusInfo lastStatus;
     static uint32_t lastLog = 0;
     uint32_t now = millis();
 
     serialCommands();
+    remoteCommands();
+    noteStableOnce(now);
+    uploadStep();
     printListingWhenReady();
     M5Cardputer.update();
     if (M5Cardputer.Keyboard.isChange()) {
@@ -262,15 +605,43 @@ void loop() {
 
     if (now - lastLog > 10000) {
         lastLog = now;
-        Serial.printf("status: heap %u min %u\n", ESP.getFreeHeap(), ESP.getMinFreeHeap());
+        console.printf("status: heap %u min %u\n", ESP.getFreeHeap(), ESP.getMinFreeHeap());
+    }
+
+    // Firmware Update: its progress takes over the screen, then the device restarts when it's safe.
+    static int shownPercent = -1;
+    static uint32_t installedAt = 0;
+    static bool redrawAfterUpdate = false;
+    switch (update->phase()) {
+        case UpdateService::Phase::Receiving:
+            if (update->percent() != shownPercent) {
+                shownPercent = update->percent();
+                screen.renderUpdate("Firmware update", "Receiving " + update->incomingVersion(), shownPercent);
+            }
+            redrawAfterUpdate = true;
+            return;
+        case UpdateService::Phase::Installed:
+            if (!installedAt) installedAt = now;
+            // Don't pull the rug out from under someone typing, for up to a minute.
+            if (!apps->foreground().textEntryActive() || now - installedAt >= 60000) {
+                screen.renderUpdate("Restarting", "into " + update->incomingVersion(), -1);
+                delay(800);
+                ESP.restart();
+            }
+            break;
+        default:
+            shownPercent = -1;
+            break;
     }
 
     if (power->screen() == ScreenState::Off) return;
     StatusInfo status = currentStatus();
     const Toast* toast = notifier->toasts().current(now);
     bool toastChanged = notifier->toasts().takeChanged();
-    if (apps->takeRedraw() || toastChanged || status != lastStatus) {
+    if (apps->takeRedraw() || toastChanged || status != lastStatus || redrawAfterUpdate) {
         lastStatus = status;
+        redrawAfterUpdate = false;
         screen.render(*apps, status, toast);
+        update->firstFrameDrawn();
     }
 }

src/platform/console.cpp

@@ -0,0 +1,86 @@
+#include "platform/console.h"
+
+#include <Arduino.h>
+
+#ifdef RORO_DEBUG
+#include <esp_log.h>
+#include <freertos/FreeRTOS.h>
+
+#include <algorithm>
+#include <cstdio>
+#endif
+
+namespace roro {
+
+Console console;
+
+#ifdef RORO_DEBUG
+namespace {
+
+// Any task may write (ESP-IDF logs come from everywhere), so the ring is behind a spinlock, held
+// only for the copy.
+portMUX_TYPE ringLock = portMUX_INITIALIZER_UNLOCKED;
+vprintf_like_t espLogNext = nullptr;
+
+int teeEspLog(const char* format, va_list args) {
+    char line[200];
+    va_list copy;
+    va_copy(copy, args);
+    int n = vsnprintf(line, sizeof line, format, copy);
+    va_end(copy);
+    if (n > 0) console.toRing(reinterpret_cast<const uint8_t*>(line), std::min<size_t>(n, sizeof line - 1));
+    return espLogNext ? espLogNext(format, args) : n;  // the serial port, as before
+}
+
+}  // namespace
+
+void Console::captureEspLogs() { espLogNext = esp_log_set_vprintf(teeEspLog); }
+
+void Console::toRing(const uint8_t* data, size_t len) {
+    if (len > kRingBytes) {
+        data += len - kRingBytes;  // only the tail can fit
+        len = kRingBytes;
+    }
+    portENTER_CRITICAL(&ringLock);
+    size_t at = head_ % kRingBytes;
+    size_t first = std::min(len, kRingBytes - at);
+    memcpy(ring_ + at, data, first);
+    memcpy(ring_, data + first, len - first);
+    head_ += len;
+    portEXIT_CRITICAL(&ringLock);
+}
+
+uint32_t Console::oldest() const {
+    portENTER_CRITICAL(&ringLock);
+    uint32_t pos = head_ > kRingBytes ? head_ - kRingBytes : 0;
+    portEXIT_CRITICAL(&ringLock);
+    return pos;
+}
+
+size_t Console::readSince(uint32_t& pos, uint8_t* out, size_t max, uint32_t& skipped) {
+    portENTER_CRITICAL(&ringLock);
+    uint32_t from = head_ > kRingBytes ? head_ - kRingBytes : 0;
+    skipped = pos < from ? from - pos : 0;
+    if (pos < from) pos = from;
+    size_t n = std::min<size_t>(max, head_ - pos);
+    size_t at = pos % kRingBytes;
+    size_t first = std::min(n, kRingBytes - at);
+    memcpy(out, ring_ + at, first);
+    memcpy(out + first, ring_, n - first);
+    pos += n;
+    portEXIT_CRITICAL(&ringLock);
+    return n;
+}
+#endif
+
+size_t Console::write(const uint8_t* data, size_t len) {
+#ifdef RORO_DEBUG
+    toRing(data, len);
+#endif
+    // Never wait for the USB host. One that's attached but not reading (a VM, a closed terminal)
+    // would stall the caller for up to 2 s per write while HWCDC retries; the ring keeps it anyway.
+    if (Serial.availableForWrite() >= static_cast<int>(len)) Serial.write(data, len);
+    return len;
+}
+
+}  // namespace roro

src/platform/console.h

@@ -0,0 +1,40 @@
+#pragma once
+
+#include <Print.h>
+
+#include <cstddef>
+#include <cstdint>
+
+namespace roro {
+
+// Where the firmware's console output goes: the USB serial port, and in a Debug Build also a ring
+// buffer the Debug Console sends over Wi-Fi (with what came before the connection, so boot messages
+// aren't lost). Use `console` instead of Serial for anything a human should be able to read remotely.
+class Console : public Print {
+   public:
+    size_t write(uint8_t c) override { return write(&c, 1); }
+    size_t write(const uint8_t* data, size_t len) override;
+    using Print::write;
+
+#ifdef RORO_DEBUG
+    static constexpr size_t kRingBytes = 4096;
+
+    // Also copies ESP-IDF's own log lines into the ring (they still reach the serial port).
+    void captureEspLogs();
+    // Copies bytes written since `pos` into `out`, and advances `pos`. A reader that fell more than
+    // the ring behind gets the oldest bytes still there, and `skipped` says how many it missed.
+    size_t readSince(uint32_t& pos, uint8_t* out, size_t max, uint32_t& skipped);
+    // The position of the oldest byte still in the ring: a new reader starts there.
+    uint32_t oldest() const;
+    // The ring only, for output that already reaches the serial port another way.
+    void toRing(const uint8_t* data, size_t len);
+
+   private:
+    uint8_t ring_[kRingBytes];
+    uint32_t head_ = 0;  // total bytes ever written; the ring holds the last kRingBytes of them
+#endif
+};
+
+extern Console console;
+
+}  // namespace roro

src/platform/crash_report.cpp

@@ -0,0 +1,66 @@
+#include "platform/crash_report.h"
+
+#include <esp_core_dump.h>
+
+#include "platform/system_info.h"
+#include "safe_mode.h"
+#include "version.h"
+
+namespace roro::crash_report {
+
+int noteBoot(KeyValueStore& store) {
+    bool crashed = system_info::resetWasCrash();
+    std::string last;
+    store.getString("run_ver", last);
+    if (crashed) {
+        store.putString("crash_ver", last.empty() ? versionString() : last);
+        store.putString("crash_why", system_info::resetReason());
+    }
+    if (last != versionString()) store.putString("run_ver", versionString());
+
+    int32_t before = 0;
+    store.getInt("crash_boots", before);
+    int now = SafeMode::countAtBoot(crashed, before);
+    if (now != before) store.putInt("crash_boots", now);
+    return now;
+}
+
+void noteStable(KeyValueStore& store) {
+    int32_t n = 0;
+    if (store.getInt("crash_boots", n) && n != 0) store.putInt("crash_boots", 0);
+}
+
+void print(Print& out, KeyValueStore& store) {
+    std::string version, why;
+    store.getString("crash_ver", version);
+    store.getString("crash_why", why);
+    if (version.empty()) out.println("crash: none recorded");
+    else out.printf("crash: last one in %s (%s)\n", version.c_str(), why.c_str());
+
+    esp_core_dump_summary_t sum;
+    if (esp_core_dump_image_check() != ESP_OK || esp_core_dump_get_summary(&sum) != ESP_OK) {
+        out.println("crash: no core dump in flash");
+        return;
+    }
+    char reason[160] = "";
+    esp_core_dump_get_panic_reason(reason, sizeof reason);
+    out.printf("crash: task %s, pc 0x%08lx, cause %lu, address 0x%08lx\n", sum.exc_task, (unsigned long)sum.exc_pc,
+               (unsigned long)sum.ex_info.exc_cause, (unsigned long)sum.ex_info.exc_vaddr);
+    if (reason[0]) out.printf("crash: reason: %s\n", reason);
+    out.print("crash: backtrace");
+    for (uint32_t i = 0; i < sum.exc_bt_info.depth && i < 16; i++) out.printf(" 0x%08lx", (unsigned long)sum.exc_bt_info.bt[i]);
+    out.println(sum.exc_bt_info.corrupted ? " (corrupted)" : "");
+    out.printf("crash: elf sha256 %s\n", reinterpret_cast<const char*>(sum.app_elf_sha256));
+}
+
+std::string headline() {
+    esp_core_dump_summary_t sum;
+    std::string where = "";
+    if (esp_core_dump_image_check() == ESP_OK && esp_core_dump_get_summary(&sum) == ESP_OK)
+        where = std::string(" in ") + sum.exc_task;
+    return std::string("Restarted after a ") + system_info::resetReason() + where;
+}
+
+bool erase() { return esp_core_dump_image_erase() == ESP_OK; }
+
+}  // namespace roro::crash_report

src/platform/crash_report.h

@@ -0,0 +1,26 @@
+#pragma once
+
+#include <Print.h>
+
+#include <string>
+
+#include "key_value_store.h"
+
+namespace roro::crash_report {
+
+// First thing at boot: remembers which version runs, and after a crash restart, which version
+// crashed (the one that ran last time, even if a Rollback has switched slots since). Returns how
+// many starts in a row ended in a crash, for Safe Mode.
+int noteBoot(KeyValueStore& store);
+// The device has been up long enough: the crash streak is over.
+void noteStable(KeyValueStore& store);
+
+// The last crash: which firmware, why, and the task, PC and backtrace from the core dump in flash.
+// Decode the backtrace on the PC with scripts/decode_backtrace.sh <version> <addresses>.
+void print(Print& out, KeyValueStore& store);
+// One line for a Notification after a crash restart, e.g. "Restarted after a crash in loopTask".
+std::string headline();
+// Forgets the core dump, so the next crash's is the one kept.
+bool erase();
+
+}  // namespace roro::crash_report

src/platform/ota_device.cpp

@@ -0,0 +1,44 @@
+#include "ota_device.h"
+
+#include <cstring>
+
+#include "ota_public_key.h"
+
+namespace roro {
+
+EcdsaVerifier::EcdsaVerifier() {
+    mbedtls_pk_init(&key_);
+    // PEM parsing wants the terminating NUL counted in the length.
+    ready_ = mbedtls_pk_parse_public_key(&key_, reinterpret_cast<const unsigned char*>(kOtaPublicKeyPem),
+                                         std::strlen(kOtaPublicKeyPem) + 1) == 0;
+}
+
+EcdsaVerifier::~EcdsaVerifier() { mbedtls_pk_free(&key_); }
+
+bool EcdsaVerifier::verify(const uint8_t digest[32], const uint8_t* signature, size_t len) {
+    return ready_ && mbedtls_pk_verify(&key_, MBEDTLS_MD_SHA256, digest, 32, signature, len) == 0;
+}
+
+bool EspOtaSink::begin(size_t imageSize) {
+    if (!slot_) return false;
+    open_ = esp_ota_begin(slot_, imageSize, &handle_) == ESP_OK;
+    return open_;
+}
+
+bool EspOtaSink::write(const uint8_t* data, size_t len) {
+    return open_ && esp_ota_write(handle_, data, len) == ESP_OK;
+}
+
+bool EspOtaSink::finish() {
+    if (!open_) return false;
+    open_ = false;
+    // esp_ota_end() also validates the image structure (segments, checksum) for this chip.
+    return esp_ota_end(handle_) == ESP_OK && esp_ota_set_boot_partition(slot_) == ESP_OK;
+}
+
+void EspOtaSink::abort() {
+    if (open_) esp_ota_abort(handle_);
+    open_ = false;
+}
+
+}  // namespace roro

src/platform/ota_device.h

@@ -0,0 +1,38 @@
+#pragma once
+
+#include <esp_ota_ops.h>
+#include <mbedtls/pk.h>
+
+#include "update_parser.h"
+
+namespace roro {
+
+// Checks Update File signatures against the public key compiled into the firmware (ADR 0003).
+class EcdsaVerifier : public SignatureVerifier {
+   public:
+    EcdsaVerifier();
+    ~EcdsaVerifier() override;
+    bool verify(const uint8_t digest[32], const uint8_t* signature, size_t len) override;
+
+   private:
+    mbedtls_pk_context key_;
+    bool ready_ = false;
+};
+
+// Writes the image to the app slot that isn't running, and makes it the next boot on finish().
+class EspOtaSink : public UpdateSink {
+   public:
+    EspOtaSink() : slot_(esp_ota_get_next_update_partition(nullptr)) {}
+    size_t capacity() const { return slot_ ? slot_->size : 0; }
+    bool begin(size_t imageSize) override;
+    bool write(const uint8_t* data, size_t len) override;
+    bool finish() override;
+    void abort() override;
+
+   private:
+    const esp_partition_t* slot_;
+    esp_ota_handle_t handle_ = 0;
+    bool open_ = false;
+};
+
+}  // namespace roro

src/platform/ota_public_key.h

@@ -0,0 +1,12 @@
+#pragma once
+
+// Public key that Firmware Updates must be signed for (ECDSA P-256). Generated by
+// scripts/ota_keygen.sh; the private key is not in this repository (ADR 0003).
+namespace roro {
+inline constexpr char kOtaPublicKeyPem[] =
+    "-----BEGIN PUBLIC KEY-----\n"
+    "MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEIWzT07fvTpQxWjTdewMipYH6f42+\n"
+    "mM8niHm+T8y+Mvjanb3H8hpYXg3VjuJGFtcHw/hFX0Q2f2AiSHMF0DhMbQ==\n"
+    "-----END PUBLIC KEY-----\n"
+    ;
+}  // namespace roro

src/platform/system_info.cpp

@@ -0,0 +1,118 @@
+#include "platform/system_info.h"
+
+#include <Arduino.h>
+#include <esp_heap_caps.h>
+#include <esp_ota_ops.h>
+#include <esp_system.h>
+#include <freertos/FreeRTOS.h>
+#include <freertos/task.h>
+
+#include <string>
+#include <vector>
+
+#include "version.h"
+
+namespace roro::system_info {
+
+const char* resetReason() {
+    switch (esp_reset_reason()) {
+        case ESP_RST_POWERON: return "power-on";
+        case ESP_RST_EXT: return "reset pin";
+        case ESP_RST_SW: return "restart";
+        case ESP_RST_PANIC: return "panic";
+        case ESP_RST_INT_WDT: return "interrupt watchdog";
+        case ESP_RST_TASK_WDT: return "task watchdog";
+        case ESP_RST_WDT: return "watchdog";
+        case ESP_RST_DEEPSLEEP: return "deep sleep";
+        case ESP_RST_BROWNOUT: return "brownout";
+        case ESP_RST_SDIO: return "sdio";
+        case ESP_RST_USB: return "usb";
+        case ESP_RST_JTAG: return "jtag";
+        default: return "unknown";
+    }
+}
+
+bool resetWasCrash() {
+    switch (esp_reset_reason()) {
+        case ESP_RST_PANIC:
+        case ESP_RST_INT_WDT:
+        case ESP_RST_TASK_WDT:
+        case ESP_RST_WDT: return true;
+        default: return false;
+    }
+}
+
+static const char* stateName(esp_ota_img_states_t s) {
+    switch (s) {
+        case ESP_OTA_IMG_NEW: return "new";
+        case ESP_OTA_IMG_PENDING_VERIFY: return "pending verify";
+        case ESP_OTA_IMG_VALID: return "valid";
+        case ESP_OTA_IMG_INVALID: return "invalid";
+        case ESP_OTA_IMG_ABORTED: return "aborted";
+        default: return "undefined";
+    }
+}
+
+void printSystem(Print& out) {
+    uint32_t s = millis() / 1000;
+    out.printf("firmware: %s %s\n", kProductName, versionString());
+    out.printf("uptime: %luh%02lum%02lus, last start: %s\n", (unsigned long)(s / 3600), (unsigned long)(s / 60 % 60),
+               (unsigned long)(s % 60), resetReason());
+    out.printf("heap: %u free, %u lowest, %u largest block\n", ESP.getFreeHeap(), ESP.getMinFreeHeap(),
+               (unsigned)heap_caps_get_largest_free_block(MALLOC_CAP_8BIT));
+    out.printf("chip: %s rev %d, %lu MHz, %.1f C\n", ESP.getChipModel(), ESP.getChipRevision(),
+               (unsigned long)ESP.getCpuFreqMHz(), temperatureRead());
+}
+
+static std::string slotKey(const esp_partition_t* slot) { return std::string("ver_") + slot->label; }
+
+void recordSlotVersion(KeyValueStore& store, const esp_partition_t* slot, const char* version) {
+    std::string known;
+    if (slot && !(store.getString(slotKey(slot).c_str(), known) && known == version))
+        store.putString(slotKey(slot).c_str(), version);
+}
+
+void printSlots(Print& out, KeyValueStore& store) {
+    const esp_partition_t* running = esp_ota_get_running_partition();
+    const esp_partition_t* next = esp_ota_get_boot_partition();
+    esp_partition_iterator_t it = esp_partition_find(ESP_PARTITION_TYPE_APP, ESP_PARTITION_SUBTYPE_ANY, nullptr);
+    for (; it; it = esp_partition_next(it)) {  // the last next() releases the iterator
+        const esp_partition_t* p = esp_partition_get(it);
+        esp_app_desc_t desc;
+        bool hasApp = esp_ota_get_partition_description(p, &desc) == ESP_OK;
+        std::string version = "(unknown version)";
+        store.getString(slotKey(p).c_str(), version);
+        esp_ota_img_states_t state;
+        bool hasState = esp_ota_get_state_partition(p, &state) == ESP_OK;
+        out.printf("slot %s: %s%s%s, %s\n", p->label, hasApp ? version.c_str() : "(empty)", p == running ? ", running" : "",
+                   p == next ? ", boots next" : "", hasState ? stateName(state) : "no OTA state");
+    }
+}
+
+void printTasks(Print& out) {
+    UBaseType_t n = uxTaskGetNumberOfTasks();
+    std::vector<TaskStatus_t> tasks(n + 4);
+    uint32_t total = 0;
+    n = uxTaskGetSystemState(tasks.data(), tasks.size(), &total);
+    out.printf("%-16s %-4s %3s %6s %5s %s\n", "task", "st", "pri", "stack", "cpu%", "core");
+    static const char kStates[] = "RrBSD";  // running, ready, blocked, suspended, deleted
+    for (UBaseType_t i = 0; i < n; i++) {
+        const TaskStatus_t& t = tasks[i];
+        unsigned cpu = total ? (unsigned)((uint64_t)t.ulRunTimeCounter * 100 / total) : 0;
+        int core = t.xCoreID == tskNO_AFFINITY ? -1 : (int)t.xCoreID;
+        out.printf("%-16s %-4c %3u %6u %5u %d\n", t.pcTaskName, t.eCurrentState < 5 ? kStates[t.eCurrentState] : '?',
+                   (unsigned)t.uxCurrentPriority, (unsigned)t.usStackHighWaterMark, cpu, core);
+    }
+}
+
+const char* bootOtherSlot() {
+    const esp_partition_t* other = esp_ota_get_next_update_partition(nullptr);
+    esp_app_desc_t desc;
+    if (!other || esp_ota_get_partition_description(other, &desc) != ESP_OK) return "the other slot is empty";
+    if (esp_ota_set_boot_partition(other) != ESP_OK) return "the other slot doesn't hold a valid image";
+    delay(200);
+    esp_restart();
+    return "";
+}
+
+}  // namespace roro::system_info

src/platform/system_info.h

@@ -0,0 +1,29 @@
+#pragma once
+
+#include <Print.h>
+#include <esp_partition.h>
+
+#include "key_value_store.h"
+
+namespace roro::system_info {
+
+// Why the chip last started: "power-on", "panic", "task watchdog", "brownout"...
+const char* resetReason();
+// True if the last start was a crash or a watchdog, not a power-on or a deliberate restart.
+bool resetWasCrash();
+
+// Firmware, uptime and memory, one fact per line.
+void printSystem(Print& out);
+// Both app slots: which one runs, which boots next, and each one's version and OTA state. Versions
+// come from NVS ("ver_<slot>"): the prebuilt framework stamps every image with its own version.
+void printSlots(Print& out, KeyValueStore& store);
+// Remembers which version the running slot holds (call at boot), or the slot an update just wrote.
+void recordSlotVersion(KeyValueStore& store, const esp_partition_t* slot, const char* version);
+// FreeRTOS tasks: state, priority, lowest free stack, CPU share since boot.
+void printTasks(Print& out);
+
+// Boots the firmware in the other app slot if it holds a valid image (a manual Rollback).
+// Returns an error message; on success it restarts and doesn't return.
+const char* bootOtherSlot();
+
+}  // namespace roro::system_info

src/services/debug_console.cpp

@@ -0,0 +1,286 @@
+#ifdef RORO_DEBUG
+
+#include "services/debug_console.h"
+
+#include <WiFi.h>
+
+#include <algorithm>
+#include <esp_core_dump.h>
+#include <esp_flash.h>
+
+#include <SD.h>
+#include <unistd.h>
+
+#include <atomic>
+#include <memory>
+
+#include "file_receiver.h"
+#include "platform/console.h"
+#include "version.h"
+
+namespace roro {
+
+namespace {
+
+constexpr uint32_t kAuthTimeoutMs = 10000;
+constexpr size_t kMaxLine = 240;
+constexpr size_t kMaxQueued = 8;
+
+// Compares without stopping at the first difference, so timing says nothing about the token.
+bool sameToken(const std::string& a, const char* b) {
+    size_t n = strlen(b);
+    uint8_t diff = a.size() != n;
+    for (size_t i = 0; i < n; i++) diff |= (i < a.size() ? a[i] : 0) ^ b[i];
+    return diff == 0;
+}
+
+// Reads one line (without its \r\n) within `timeoutMs`; false on a timeout, a drop or an overlong line.
+bool readLine(NetworkClient& c, std::string& line, uint32_t timeoutMs) {
+    line.clear();
+    uint32_t since = millis();
+    while (c.connected() && millis() - since < timeoutMs) {
+        int ch = c.read();
+        if (ch < 0) {
+            delay(10);
+            continue;
+        }
+        if (ch == '\n') {
+            if (!line.empty() && line.back() == '\r') line.pop_back();
+            return true;
+        }
+        if (line.size() >= kMaxLine) return false;
+        line += static_cast<char>(ch);
+    }
+    return false;
+}
+
+// The raw core dump partition contents, as esp-coredump reads them ("-t raw").
+void sendCoreDump(NetworkClient& client) {
+    size_t addr = 0, size = 0;
+    if (esp_core_dump_image_check() != ESP_OK || esp_core_dump_image_get(&addr, &size) != ESP_OK) {
+        client.print("coredump: none\n");
+        return;
+    }
+    client.printf("coredump: data %u\n", (unsigned)size);
+    uint8_t buf[1024];
+    for (size_t off = 0; off < size;) {
+        size_t n = std::min(sizeof buf, size - off);
+        if (esp_flash_read(nullptr, buf, addr + off, n) != ESP_OK) break;  // the host sees a short file
+        if (client.write(buf, n) != n) return;
+        off += n;
+    }
+    client.print("coredump: end\n");
+}
+
+}  // namespace
+
+DebugConsole::DebugConsole(WifiService& wifi, StorageService& storage)
+    : wifi_(wifi), storage_(storage), lock_(xSemaphoreCreateMutex()) {}
+
+void DebugConsole::start() {
+    console.captureEspLogs();
+    if (!task_) xTaskCreate(taskEntry, "debug", 6144, this, 1, &task_);
+}
+
+bool DebugConsole::takeCommand(std::string& line) {
+    xSemaphoreTake(lock_, portMAX_DELAY);
+    bool any = !commands_.empty();
+    if (any) {
+        line = std::move(commands_.front());
+        commands_.pop_front();
+    }
+    xSemaphoreGive(lock_);
+    return any;
+}
+
+void DebugConsole::taskEntry(void* self) { static_cast<DebugConsole*>(self)->listen(); }
+
+void DebugConsole::listen() {
+    NetworkServer server(kPort);
+    bool listening = false;
+    for (;;) {
+        bool up = wifi_.state() == WifiController::State::Connected;
+        if (up && !listening) {
+            server.begin();
+            listening = true;
+        } else if (!up && listening) {
+            server.end();
+            listening = false;
+        }
+        if (listening) {
+            NetworkClient client = server.accept();
+            if (client) {
+                client.setNoDelay(true);
+                if (authenticate(client)) serve(client);
+                client.stop();
+            }
+        }
+        vTaskDelay(pdMS_TO_TICKS(200));
+    }
+}
+
+bool DebugConsole::authenticate(NetworkClient& client) {
+    std::string token;
+    if (readLine(client, token, kAuthTimeoutMs) && sameToken(token, RORO_DEBUG_TOKEN)) return true;
+    console.printf("debug: refused a client from %s\n", client.remoteIP().toString().c_str());
+    delay(1000);  // no quick retries
+    client.print("denied\n");
+    return false;
+}
+
+void DebugConsole::serve(NetworkClient& client) {
+    console.printf("debug: client %s connected\n", client.remoteIP().toString().c_str());
+    client.printf("%s %s debug console. 'help' lists the commands. Backlog follows.\n", kProductName, versionString());
+    connected_ = true;
+    uint32_t pos = console.oldest();
+    uint8_t buf[512];
+    std::string line;
+    while (client.connected()) {
+        // Console output since last time, including the replies to this client's commands.
+        uint32_t skipped = 0;
+        size_t n;
+        while ((n = console.readSince(pos, buf, sizeof buf, skipped)) > 0) {
+            if (skipped) client.printf("\n[... %u bytes lost: the console ran faster than the network]\n", (unsigned)skipped);
+            if (client.write(buf, n) != n) break;
+        }
+        // Commands, one line at a time.
+        while (client.available()) {
+            int ch = client.read();
+            if (ch == '\r') continue;
+            if (ch != '\n') {
+                if (line.size() < kMaxLine) line += static_cast<char>(ch);
+                continue;
+            }
+            if (line == "quit" || line == "exit") {
+                client.stop();
+                break;
+            }
+            if (binaryCommand(client, line)) {
+                line.clear();
+                continue;
+            }
+            xSemaphoreTake(lock_, portMAX_DELAY);
+            bool full = commands_.size() >= kMaxQueued;
+            if (!full && !line.empty()) commands_.push_back(line);
+            xSemaphoreGive(lock_);
+            if (full) client.print("debug: busy, command dropped\n");
+            line.clear();
+        }
+        vTaskDelay(pdMS_TO_TICKS(20));
+    }
+    connected_ = false;
+    console.println("debug: client disconnected");
+}
+
+bool DebugConsole::binaryCommand(NetworkClient& client, const std::string& line) {
+    if (line == "reset") {  // works even when the main loop is stuck
+        client.print("debug: restarting now\n");
+        client.flush();
+        delay(200);
+        esp_restart();
+    }
+    if (line == "coredump get") sendCoreDump(client);
+    else if (line.rfind("get ", 0) == 0) get(client, line.substr(4));
+    else if (line.rfind("put ", 0) == 0) put(client, line.substr(4));
+    else if (line == "screenshot") screenshot(client);
+    else return false;
+    return true;
+}
+
+bool DebugConsole::onStorage(std::function<void()> job) { return storage_.runAndWait(std::move(job)); }
+
+void DebugConsole::get(NetworkClient& client, const std::string& path) {
+    bool ran = onStorage([&]() {
+        File f = SD.open(path.c_str());
+        if (!f || f.isDirectory()) return (void)client.printf("get: error cannot open %s\n", path.c_str());
+        size_t size = f.size();
+        client.printf("get: data %u\n", (unsigned)size);
+        uint8_t buf[1024];
+        for (size_t sent = 0; sent < size;) {
+            int n = f.read(buf, std::min(sizeof buf, size - sent));
+            if (n <= 0 || client.write(buf, n) != static_cast<size_t>(n)) break;  // the host sees it short
+            sent += n;
+        }
+        f.close();
+        client.print("get: end\n");
+    });
+    if (!ran) client.print("get: error no SD card\n");
+}
+
+// The same checks as `sd put` over serial (FileReceiver), but TCP does the flow control, so the
+// file is written in one job with the file kept open.
+void DebugConsole::put(NetworkClient& client, const std::string& args) {
+    FileReceiver r;
+    std::string error = r.begin(args, millis());
+    StorageState card = storage_.state();
+    if (error.empty() && !card.present) error = "no SD card";
+    if (error.empty() && card.totalBytes - card.usedBytes < r.size() + 64 * 1024) error = "not enough space";
+    if (!error.empty()) return (void)client.printf("put: error %s\n", error.c_str());
+
+    bool ran = onStorage([&]() {
+        std::string part = r.partPath();
+        for (size_t slash = part.find('/', 1); slash != std::string::npos; slash = part.find('/', slash + 1)) {
+            std::string dir = part.substr(0, slash);
+            if (!SD.exists(dir.c_str())) SD.mkdir(dir.c_str());
+        }
+        File f = SD.open(part.c_str(), FILE_WRITE);
+        if (!f) return (void)client.print("put: error card not writable\n");
+        client.printf("put: ready %u\n", (unsigned)r.size());
+        uint8_t buf[1024];
+        using S = FileReceiver::State;
+        while (r.state() == S::Receiving || r.state() == S::Writing) {
+            if (r.state() == S::Writing) {
+                const auto& c = r.chunk();
+                bool ok = f.write(c.data(), c.size()) == c.size();
+                // A card can fail one write and take the next. FATFS keeps a failed file in error,
+                // so: close, cut back to the last good byte, reopen, try again.
+                for (int retry = 1; !ok && retry <= 3; retry++) {
+                    console.printf("put: write failed at %u, retry %d\n", (unsigned)r.received(), retry);
+                    f.close();
+                    delay(50 * retry);
+                    truncate(("/sd" + part).c_str(), r.received());
+                    f = SD.open(part.c_str(), FILE_APPEND);
+                    ok = f && f.size() == r.received() && f.write(c.data(), c.size()) == c.size();
+                }
+                r.chunkWritten(ok, millis());
+                continue;
+            }
+            int n = client.read(buf, std::min(sizeof buf, r.wanted()));
+            if (n > 0) r.feed(buf, n, millis());
+            else if (!client.connected()) break;
+            else {
+                delay(2);
+                r.tick(millis());
+            }
+        }
+        f.close();
+        if (r.state() == S::Finishing) {
+            if (SD.exists(r.path().c_str())) SD.remove(r.path().c_str());
+            r.finished(SD.rename(part.c_str(), r.path().c_str()));
+        }
+        if (r.state() == S::Done) client.printf("put: done %s %u B\n", r.path().c_str(), (unsigned)r.size());
+        else {
+            SD.remove(part.c_str());
+            client.printf("put: error %s\n", r.error().empty() ? "connection lost" : r.error().c_str());
+            // The rest of the file is still on its way: never read it as commands.
+            client.flush();
+            client.stop();
+        }
+    });
+    if (!ran) client.print("put: error no SD card\n");
+}
+
+// The frame as composed off-screen (RGB332, one byte a pixel). Read while the UI may be drawing,
+// so it can tear; it's for looking, not for pixel-exact tests.
+void DebugConsole::screenshot(NetworkClient& client) {
+    const uint8_t* pixels = frame_ ? static_cast<const uint8_t*>(frame_->getBuffer()) : nullptr;
+    if (!pixels) return (void)client.print("screenshot: error no frame\n");
+    int w = frame_->width(), h = frame_->height();
+    client.printf("screenshot: rgb332 %d %d\n", w, h);
+    for (int y = 0; y < h; y += 16) client.write(pixels + y * w, w * std::min(16, h - y));
+    client.print("screenshot: end\n");
+}
+
+}  // namespace roro
+
+#endif

src/services/debug_console.h

@@ -0,0 +1,67 @@
+#pragma once
+
+#ifdef RORO_DEBUG
+
+#include <freertos/FreeRTOS.h>
+#include <freertos/semphr.h>
+
+#include <deque>
+#include <functional>
+#include <string>
+
+#include "service.h"
+#include "services/storage_service.h"
+#include "services/wifi_service.h"
+#include "ui/canvas.h"
+
+class NetworkClient;
+
+namespace roro {
+
+// Debug Builds only (ADR 0004): the console over Wi-Fi, on TCP 2323 while Wi-Fi is Connected. A
+// client sends the debug token as its first line, then gets the recent console backlog, every new
+// console line, and runs the same commands as the serial port. One client at a time.
+//
+// The socket lives on this Service's own task; commands are handed to the main loop (takeCommand),
+// which runs them where touching Apps and Services is safe. Their output reaches the client
+// through the console ring like everything else.
+class DebugConsole : public Service {
+   public:
+    static constexpr uint16_t kPort = 2323;
+
+    DebugConsole(WifiService& wifi, StorageService& storage);
+    // The off-screen frame the UI composes into: `screenshot` sends it as it stands.
+    void setFrame(Canvas& frame) { frame_ = &frame; }
+    const char* name() const override { return "debug"; }
+    void start() override;
+
+    // The next command line a client sent, for the main loop to run.
+    bool takeCommand(std::string& line);
+    bool clientConnected() const { return connected_; }
+
+   private:
+    static void taskEntry(void* self);
+    void listen();
+    void serve(::NetworkClient& client);
+    bool authenticate(::NetworkClient& client);
+    // Binary commands, answered on this task: true if `line` was one.
+    bool binaryCommand(::NetworkClient& client, const std::string& line);
+    // Runs `job` on the storage task (where card access is safe) and waits for it. False if the
+    // card isn't mounted, in which case the storage task never runs it.
+    bool onStorage(std::function<void()> job);
+    void get(::NetworkClient& client, const std::string& path);
+    void put(::NetworkClient& client, const std::string& args);
+    void screenshot(::NetworkClient& client);
+
+    WifiService& wifi_;
+    StorageService& storage_;
+    Canvas* frame_ = nullptr;
+    TaskHandle_t task_ = nullptr;
+    SemaphoreHandle_t lock_;
+    std::deque<std::string> commands_;
+    volatile bool connected_ = false;
+};
+
+}  // namespace roro
+
+#endif

src/services/gemini_service.cpp

@@ -0,0 +1,803 @@
+#include "services/gemini_service.h"
+
+#include <NetworkClientSecure.h>
+#include <SD.h>
+#include <WiFi.h>
+#include <esp_heap_caps.h>
+
+#include <algorithm>
+#include <map>
+
+#include "gemini_url.h"
+#include "gemtext.h"
+#include "platform/console.h"
+#include "sha256.h"
+#include "storage_paths.h"
+
+namespace roro {
+
+using gemini::TextBuffer;
+
+namespace {
+
+constexpr uint32_t kIdleTimeoutMs = 15000;
+constexpr const char* kSavedRoot = "/gemini/saved";
+constexpr const char* kSavedMark = "> Saved from ";  // first line of a Saved Page (Q82)
+constexpr const char* kDefaults =
+    "## Start here\n"
+    "=> gemini://geminiprotocol.net/ Project Gemini\n"
+    "=> gemini://kennedy.gemi.dev/ Kennedy: search Geminispace\n"
+    "=> gemini://skyjake.fi/~Cosmos/ Cosmos: what's new on Geminispace\n"
+    "=> gemini://bbs.geminispace.org/ Bubble: a bulletin board\n";
+
+std::string hex(const uint8_t* data, size_t len) {
+    static const char* digits = "0123456789abcdef";
+    std::string out;
+    for (size_t i = 0; i < len; i++) {
+        out += digits[data[i] >> 4];
+        out += digits[data[i] & 15];
+    }
+    return out;
+}
+
+// Folders for a file path, one at a time (SD.mkdir makes one level).
+void makeParents(const std::string& path) {
+    for (size_t slash = path.find('/', 1); slash != std::string::npos; slash = path.find('/', slash + 1)) {
+        std::string dir = path.substr(0, slash);
+        if (!SD.exists(dir.c_str())) SD.mkdir(dir.c_str());
+    }
+}
+
+// Copies `from` to `to`, optionally after a first line. On the storage task.
+bool copyFile(const char* from, const std::string& to, const std::string& firstLine) {
+    File in = SD.open(from);
+    if (!in) return false;
+    makeParents(to);
+    File out = SD.open(to.c_str(), FILE_WRITE);
+    if (!out) return false;
+    bool ok = firstLine.empty() || out.print((firstLine + "\n").c_str()) > 0;
+    uint8_t buf[512];
+    int n;
+    while (ok && (n = in.read(buf, sizeof buf)) > 0) ok = out.write(buf, n) == static_cast<size_t>(n);
+    out.close();
+    in.close();
+    if (!ok) SD.remove(to.c_str());
+    return ok;
+}
+
+struct SavedEntry {
+    std::string path;  // /gemini/saved/host/…/name.gmi
+    time_t when;
+};
+
+void listSaved(const std::string& dir, std::vector<SavedEntry>& out) {
+    File d = SD.open(dir.c_str());
+    if (!d || !d.isDirectory()) return;
+    for (File f = d.openNextFile(); f && out.size() < 200; f = d.openNextFile()) {
+        std::string path = dir + "/" + f.name();
+        if (f.isDirectory()) listSaved(path, out);
+        else out.push_back({path, f.getLastWrite()});
+    }
+}
+
+}  // namespace
+
+const char* GeminiService::slotPath(int slot) {
+    static const char* const kPaths[] = {"/gemini/cache/page0.gmi", "/gemini/cache/page1.gmi", "/gemini/cache/work.gmi"};
+    return kPaths[slot];
+}
+
+const char* GeminiService::cacheOf(const std::string& url) const {
+    for (int s = 0; s < 3; s++)
+        if (!url.empty() && slotUrl_[s] == url) return slotPath(s);
+    return nullptr;
+}
+
+GeminiService::GeminiService(KeyValueStore& store, StorageService& storage, ClockService& clock, EventBus& bus)
+    : store_(store), storage_(storage), clock_(clock), bus_(bus), lock_(xSemaphoreCreateMutex()) {}
+
+// NVS keys are 15 characters at most: "gm" and 12 hex digits of SHA-256("host:port").
+std::string GeminiService::pinKey(const std::string& host, int port) const {
+    std::string id = host + ":" + std::to_string(port);
+    uint8_t digest[32];
+    Sha256::hash(reinterpret_cast<const uint8_t*>(id.data()), id.size(), digest);
+    return "gm" + hex(digest, 6);
+}
+
+void GeminiService::trust(const std::string& host, int port, const std::string& fingerprint) {
+    store_.putString(pinKey(host, port).c_str(), fingerprint);
+}
+
+std::string GeminiService::now() const {
+    int64_t t = clock_.utcNow();
+    return t < 0 ? "an unknown date" : ClockModel::formatLocalDate(t) + " " + ClockModel::formatLocalTime(t);
+}
+
+void GeminiService::notify(const std::string& text) {
+    bus_.publish(Event::withText(EventType::Notification, text.c_str(), static_cast<int32_t>(NotificationLevel::Info)));
+}
+
+bool GeminiService::start(Job job) {
+    if (busy_) return false;
+    busy_ = true;
+    ready_ = messageReady_ = cancel_ = false;
+    job_ = job;
+    if (xTaskCreate(taskEntry, "gemini", 6144, this, 1, nullptr) != pdPASS) {  // peak 3.6 KB (step 1)
+        busy_ = false;
+        return false;
+    }
+    return true;
+}
+
+bool GeminiService::fetch(const std::string& url, bool preferSaved) {
+    if (busy_) return false;
+    arg_ = url;
+    preferSaved_ = preferSaved;
+    return start(Job::Fetch);
+}
+
+bool GeminiService::fetchToConsole(const std::string& url) {
+    if (busy_) return false;
+    toConsole_ = true;
+    if (!fetch(url)) {
+        toConsole_ = false;
+        return false;
+    }
+    return true;
+}
+
+bool GeminiService::save(const std::string& url) {
+    if (busy_) return false;
+    arg_ = url;
+    return start(Job::Save);
+}
+
+bool GeminiService::saveWithLinks(const std::string& url, std::vector<std::string> links) {
+    if (busy_) return false;
+    arg_ = url;
+    links_ = std::move(links);
+    return start(Job::SaveWithLinks);
+}
+
+bool GeminiService::refresh(const std::string& savedPath) {
+    if (busy_) return false;
+    arg_ = savedPath;
+    return start(Job::Refresh);
+}
+
+bool GeminiService::deleteSaved(const std::string& savedPath) {
+    if (busy_) return false;
+    arg_ = savedPath;
+    return start(Job::Delete);
+}
+
+bool GeminiService::addBookmark(const std::string& url, const std::string& title) {
+    if (busy_) return false;
+    arg_ = url;
+    arg2_ = title;
+    return start(Job::Bookmark);
+}
+
+bool GeminiService::download(const std::string& url) {
+    if (busy_) return false;
+    arg_ = url;
+    return start(Job::Download);
+}
+
+bool GeminiService::loadWindow(const GeminiPage& page, size_t firstLine) {
+    if (busy_ || page.backing.empty()) return false;
+    windowPage_ = GeminiPage();
+    windowPage_.backing = page.backing;
+    windowPage_.totalLines = page.totalLines;
+    windowPage_.lineIndex = page.lineIndex;
+    windowLine_ = firstLine;
+    // The App drops its current window once the new one is in: count that memory as coming back.
+    windowReleasing_ = page.text.bytes() + page.text.lineCount() * 8;
+    return start(Job::Window);
+}
+
+bool GeminiService::takeResult(GeminiPage& out) {
+    if (!ready_) return false;
+    xSemaphoreTake(lock_, portMAX_DELAY);
+    out = std::move(result_);
+    result_ = GeminiPage();
+    ready_ = false;
+    xSemaphoreGive(lock_);
+    return true;
+}
+
+bool GeminiService::takeMessage(std::string& out) {
+    if (!messageReady_) return false;
+    xSemaphoreTake(lock_, portMAX_DELAY);
+    out = std::move(message_);
+    messageReady_ = false;
+    xSemaphoreGive(lock_);
+    return true;
+}
+
+void GeminiService::finishWithMessage(const std::string& text) {
+    xSemaphoreTake(lock_, portMAX_DELAY);
+    message_ = text;
+    messageReady_ = true;
+    xSemaphoreGive(lock_);
+}
+
+void GeminiService::taskEntry(void* self) {
+    static_cast<GeminiService*>(self)->run();
+    vTaskDelete(nullptr);
+}
+
+void GeminiService::run() {
+    switch (job_) {
+        case Job::Fetch: {
+            GeminiPage page;
+            runFetch(page);
+            if (!toConsole_) {
+                xSemaphoreTake(lock_, portMAX_DELAY);
+                result_ = std::move(page);
+                ready_ = true;
+                xSemaphoreGive(lock_);
+            }
+            toConsole_ = false;
+            break;
+        }
+        case Job::Save: {
+            std::string why = saveCached(arg_);
+            finishWithMessage(!why.empty() ? why : replaced_ ? "Saved again (replaced the older copy)" : "Saved for offline reading");
+            break;
+        }
+        case Job::SaveWithLinks: {
+            std::string why = saveCached(arg_);
+            if (!why.empty()) {
+                finishWithMessage(why);
+                break;
+            }
+            int saved = 1, failed = 0, total = static_cast<int>(links_.size()) + 1;
+            notify("Saving " + std::to_string(total) + " pages for offline reading");
+            for (const std::string& link : links_) {
+                if (cancel_) break;
+                GeminiPage page;
+                fetchFollowing(link, page, false, kWorkSlot);
+                bool text = page.outcome == GeminiPage::Outcome::Ok &&
+                            page.header.category() == gemini::Category::Success && page.header.mimeType() == "text/gemini";
+                if (text && saveCached(link).empty()) saved++;
+                else failed++;
+                if ((saved + failed) % 5 == 0) notify("Saved " + std::to_string(saved) + " of " + std::to_string(total));
+            }
+            std::string done = "Saved " + std::to_string(saved) + " of " + std::to_string(total) + " pages" +
+                               (failed ? " (" + std::to_string(failed) + " not gemtext or failed)" : "");
+            notify(done);
+            finishWithMessage(done);
+            break;
+        }
+        case Job::Refresh: {
+            // Only the first line: where it came from. (Loading the whole page here, next to the
+            // App's copy and a TLS connection, once took the heap down to 436 bytes.)
+            std::string from = savedFrom(arg_);
+            if (from.empty()) {
+                finishWithMessage("Not a Saved Page");
+                break;
+            }
+            GeminiPage page;
+            fetchFollowing(from, page, false, kWorkSlot);
+            std::string why = page.outcome != GeminiPage::Outcome::Ok ? page.error
+                              : page.header.category() != gemini::Category::Success ? page.header.meta
+                                                                                     : saveCached(from);
+            finishWithMessage(why.empty() ? "Refreshed" : "Not refreshed: " + why);
+            break;
+        }
+        case Job::Window: {
+            // Q86 both ways: old and new together above the transient floor for a moment, and the
+            // new one alone (once the old is dropped) leaving the steady floor.
+            size_t free = esp_get_free_heap_size();
+            size_t transient = free > kTransientFloor + TextBuffer::kChunk ? free - kTransientFloor - TextBuffer::kChunk : 0;
+            size_t steady = free + windowReleasing_ > kSteadyFloor + TextBuffer::kChunk
+                                ? free + windowReleasing_ - kSteadyFloor - TextBuffer::kChunk
+                                : 0;
+            size_t budget = std::min(transient, steady);
+            GeminiPage page = std::move(windowPage_);
+            page.windowStart = windowLine_ - windowLine_ % kIndexEvery;
+            page.windowed = true;
+            page.windowOf = page.backing;
+            page.outcome = GeminiPage::Outcome::Ok;
+            readWindow(page, page.windowStart, std::min(budget, kMaxBody));
+            console.printf("gemini: window from line %u: %u lines\n", (unsigned)page.windowStart,
+                           (unsigned)page.text.lineCount());
+            xSemaphoreTake(lock_, portMAX_DELAY);
+            result_ = std::move(page);
+            ready_ = true;
+            xSemaphoreGive(lock_);
+            break;
+        }
+        case Job::Delete: {
+            bool removed = false;
+            bool ran = storage_.runAndWait([&]() { removed = SD.remove(arg_.c_str()); });
+            finishWithMessage(!ran ? "No SD card" : removed ? "Deleted" : "Not deleted");
+            break;
+        }
+        case Job::Bookmark: {
+            std::string line = "=> " + arg_ + (arg2_.empty() ? "" : " " + arg2_), already;
+            bool ran = storage_.runAndWait([&]() {
+                File f = SD.open(kBookmarks);
+                while (f && f.available()) {
+                    String l = f.readStringUntil('\n');
+                    if (l.startsWith(("=> " + arg_ + " ").c_str()) || l == ("=> " + arg_).c_str()) already = "yes";
+                }
+                if (f) f.close();
+                if (!already.empty()) return;
+                makeParents(kBookmarks);
+                File out = SD.open(kBookmarks, FILE_APPEND);
+                if (out) {
+                    out.print((line + "\n").c_str());
+                    out.close();
+                }
+            });
+            finishWithMessage(!ran ? "No SD card" : !already.empty() ? "Already bookmarked" : "Bookmarked");
+            break;
+        }
+        case Job::Download: {
+            gemini::Url u;
+            std::string name = gemini::parseUrl(arg_, u) ? u.path.substr(u.path.rfind('/') + 1) : "";
+            if (name.empty()) name = "download";
+            std::string to = "/gemini/downloads/" + storage::sanitize(name);
+            bool copied = false;
+            if (const char* from = cacheOf(arg_)) storage_.runAndWait([&]() { copied = copyFile(from, to, ""); });
+            finishWithMessage(copied ? "Saved to " + to : "Not saved (no card, or the page is gone)");
+            break;
+        }
+    }
+    busy_ = false;
+}
+
+void GeminiService::runFetch(GeminiPage& page) {
+    page.requested = arg_;
+    size_t before = esp_get_free_heap_size();
+    lowest_ = before;
+    uint32_t started = millis();
+    const std::string& url = arg_;
+    if (url == kStartUrl) composeStart(page);
+    else if (url.rfind("file://", 0) == 0) openSaved(url.substr(7), page);
+    else {
+        // Inside a Saved Page, a link to another Saved Page opens the saved copy (Q84).
+        bool savedCopy = false;
+        if (preferSaved_) {
+            std::string path = gemini::savedPath(url);
+            storage_.runAndWait([&]() { savedCopy = SD.exists(path.c_str()); });
+            if (savedCopy) openSaved(path, page);
+        }
+        if (!savedCopy) {
+            if (preferSaved_ && !WiFi.isConnected()) {
+                page.url = url;
+                page.error = "Not saved, and offline";
+            } else
+            {
+                int slot = nextDisplay_;
+                fetchFollowing(url, page, true, slot);
+                if (page.outcome == GeminiPage::Outcome::Ok && !page.cachePath.empty())
+                    nextDisplay_ = 1 - slot;  // keep this one: it backs the page on screen
+            }
+        }
+    }
+    page.ms = millis() - started;
+    if (toConsole_) report(page, before, lowest_);
+}
+
+// One request, following up to kMaxRedirects redirects.
+void GeminiService::fetchFollowing(const std::string& first, GeminiPage& page, bool loadIntoRam, int slot) {
+    std::string url = first;
+    size_t free = esp_get_free_heap_size();
+    if (free < kStartFloor) {  // Q86, for every fetch: pages, saves, refreshes
+        page.url = url;
+        page.outcome = GeminiPage::Outcome::Failed;
+        page.error = "Not enough memory (" + std::to_string(free / 1024) + " KB free): stop IRC or retry";
+        return;
+    }
+    for (int hop = 0;; hop++) {
+        fetchOne(url, page, loadIntoRam, slot);
+        if (page.outcome != GeminiPage::Outcome::Ok || page.header.category() != gemini::Category::Redirect) break;
+        std::string next = gemini::resolve(url, page.header.meta);
+        if (!gemini::isGemini(next)) {
+            page.outcome = GeminiPage::Outcome::Failed;
+            page.error = "Redirect to another protocol: " + next;
+            break;
+        }
+        if (hop + 1 > kMaxRedirects) {
+            page.outcome = GeminiPage::Outcome::Failed;
+            page.error = "Too many redirects";
+            break;
+        }
+        url = next;
+    }
+    page.url = url;
+}
+
+// A Saved Page's first line: "> Saved from <url> on <date>" (Q82). Empty if it isn't one.
+std::string GeminiService::savedFirstLine(const std::string& path) {
+    std::string first;
+    storage_.runAndWait([&]() {
+        File f = SD.open(path.c_str());
+        if (!f) return;
+        char buf[600];
+        size_t n = f.readBytesUntil('\n', buf, sizeof buf - 1);
+        buf[n] = 0;
+        first = buf;
+        f.close();
+    });
+    if (!first.empty() && first.back() == '\r') first.pop_back();
+    return first.rfind(kSavedMark, 0) == 0 ? first : "";
+}
+
+std::string GeminiService::savedFrom(const std::string& path) {
+    std::string first = savedFirstLine(path);
+    if (first.empty()) return "";
+    std::string rest = first.substr(strlen(kSavedMark));
+    return rest.substr(0, rest.find(" on "));
+}
+
+// A Saved Page from the card, as far as memory allows; its first line says where it came from.
+void GeminiService::openSaved(const std::string& path, GeminiPage& page) {
+    page.url = "file://" + path;
+    page.header.status = 20;
+    page.header.meta = "text/gemini";
+    bool found = false;
+    storage_.runAndWait([&]() { found = SD.exists(path.c_str()); });
+    std::string first = found ? savedFirstLine(path) : "";
+    if (!found) {
+        page.error = "This Saved Page is gone";
+        return;
+    }
+    if (first.rfind(kSavedMark, 0) == 0) {
+        std::string rest = first.substr(strlen(kSavedMark));
+        size_t on = rest.find(" on ");
+        page.savedFrom = rest.substr(0, on);
+        page.savedOn = on == std::string::npos ? "" : rest.substr(on + 4);
+    }
+    loadFromCard(page, esp_get_free_heap_size(), path);
+    page.outcome = GeminiPage::Outcome::Ok;
+}
+
+// about:start (Q78, Q84): bookmarks, then Saved Pages by capsule, newest first, then defaults.
+void GeminiService::composeStart(GeminiPage& page) {
+    std::string doc = "# Gemini\nTab picks a link, Enter follows it, Back returns, g types an address. "
+                      "On a page: b bookmarks it, s saves it to read offline, S with the pages it links to.\n";
+    std::string bookmarks;
+    std::vector<SavedEntry> saved;
+    bool card = storage_.runAndWait([&]() {
+        File f = SD.open(kBookmarks);
+        while (f && f.available() && bookmarks.size() < 8192) {
+            String l = f.readStringUntil('\n');
+            if (l.startsWith("=>")) bookmarks += std::string(l.c_str()) + "\n";
+        }
+        if (f) f.close();
+        listSaved(kSavedRoot, saved);
+    });
+    doc += "## Bookmarks\n";
+    doc += !card ? "No SD card: bookmarks and Saved Pages live on it.\n"
+           : bookmarks.empty() ? "None yet: b on a page adds it here.\n" : bookmarks;
+    if (!saved.empty()) {
+        // Capsules ordered by their newest Saved Page, pages newest first within each.
+        std::sort(saved.begin(), saved.end(), [](const SavedEntry& a, const SavedEntry& b) { return a.when > b.when; });
+        std::vector<std::string> order;
+        std::map<std::string, std::string> byHost;
+        size_t root = strlen(kSavedRoot) + 1;
+        for (auto& e : saved) {
+            std::string rel = e.path.substr(root);
+            std::string host = rel.substr(0, rel.find('/'));
+            if (!byHost.count(host)) order.push_back(host);
+            std::string label = rel.substr(host.size() + 1);
+            if (label.size() > 4 && label.compare(label.size() - 4, 4, ".gmi") == 0) label.resize(label.size() - 4);
+            char day[24] = "";
+            if (e.when > 1000000000) {
+                struct tm t;
+                localtime_r(&e.when, &t);
+                strftime(day, sizeof day, " (%d %b)", &t);
+            }
+            byHost[host] += "=> file://" + e.path + " " + label + day + "\n";
+        }
+        doc += "## Saved pages\n";
+        for (auto& host : order) doc += "### " + host + "\n" + byHost[host];
+    }
+    doc += kDefaults;
+    page.url = kStartUrl;
+    page.header.status = 20;
+    page.header.meta = "text/gemini";
+    page.text.append(doc.data(), doc.size());
+    page.text.finish();
+    page.outcome = GeminiPage::Outcome::Ok;
+}
+
+// The cached body of `url` (fetched again if the cache holds something else) to its Saved Page.
+std::string GeminiService::saveCached(const std::string& url) {
+    if (!gemini::isGemini(url)) return "Only Gemini pages can be saved";
+    if (!storage_.state().present) return "No SD card";
+    const char* from = cacheOf(url);
+    if (!from) {
+        GeminiPage page;
+        fetchFollowing(url, page, false, kWorkSlot);
+        if (page.outcome != GeminiPage::Outcome::Ok) return page.error;
+        if (page.header.category() != gemini::Category::Success) return page.header.meta;
+        from = cacheOf(page.url);
+        if (!from) return "Not saved";
+    }
+    std::string to = gemini::savedPath(url);
+    bool existed = false, ok = false;
+    replaced_ = false;
+    std::string header = std::string(kSavedMark) + url + " on " + now();
+    storage_.runAndWait([&]() {
+        existed = SD.exists(to.c_str());
+        ok = copyFile(from, to, header);
+    });
+    if (!ok) return "Writing to the SD card failed";
+    replaced_ = existed;  // Q82: saving again replaces it, and says so
+    return "";
+}
+
+void GeminiService::fetchOne(const std::string& url, GeminiPage& page, bool loadIntoRam, int slot) {
+    page.outcome = GeminiPage::Outcome::Failed;
+    page.text.clear();
+    page.truncated = false;
+    gemini::Url u;
+    if (!gemini::parseUrl(url, u) || u.scheme != "gemini") {
+        page.error = "Not a Gemini URL: " + url;
+        return;
+    }
+    auto track = [this]() { lowest_ = std::min<size_t>(lowest_, esp_get_free_heap_size()); };
+
+    size_t freeBefore = esp_get_free_heap_size();  // what's left once the connection closes again
+    NetworkClientSecure tls;
+    tls.setInsecure();  // trust on first use: the pinned fingerprint is what counts (Q71)
+    tls.setTimeout(15);
+    if (!tls.connect(u.host.c_str(), u.portOrDefault())) {
+        page.error = "Cannot connect to " + u.host;
+        return;
+    }
+    track();
+    uint8_t sha[32];
+    if (!tls.getFingerprintSHA256(sha)) {
+        page.error = "No certificate from " + u.host;
+        return;
+    }
+    std::string presented = hex(sha, sizeof sha), pinned;
+    std::string key = pinKey(u.host, u.portOrDefault());
+    if (!store_.getString(key.c_str(), pinned)) store_.putString(key.c_str(), presented);  // first use
+    else if (pinned != presented) {
+        page.outcome = GeminiPage::Outcome::CertificateChanged;
+        page.host = u.host;
+        page.port = u.portOrDefault();
+        page.pinned = pinned;
+        page.presented = presented;
+        page.error = "The certificate of " + u.host + " changed";
+        return;
+    }
+
+    tls.print((gemini::requestUrl(url) + "\r\n").c_str());
+    std::string header;
+    bool inBody = false;
+    uint32_t last = millis();
+    char buf[512];
+    while (!cancel_) {
+        int n = tls.available() ? tls.read(reinterpret_cast<uint8_t*>(buf), sizeof buf) : 0;
+        if (n <= 0) {
+            if (!tls.connected()) break;
+            if (millis() - last > kIdleTimeoutMs) {
+                page.error = "Timed out";
+                return;
+            }
+            delay(5);
+            continue;
+        }
+        last = millis();
+        int i = 0;
+        while (!inBody && i < n) {
+            char c = buf[i++];
+            if (c == '\n') inBody = true;
+            else if (c != '\r') header += c;
+            if (header.size() > 1100) {
+                page.error = "Malformed response header";
+                return;
+            }
+        }
+        if (!inBody) continue;
+        if (!gemini::parseHeader(header, page.header)) {
+            page.error = "Malformed response header";
+            return;
+        }
+        if (page.header.category() != gemini::Category::Success) break;  // no body to read
+        // With a card, the body goes there while the connection is open (only 4 KB in RAM),
+        // and comes back into RAM once the connection's memory is free again.
+        if (storage_.state().present) {
+            slotUrl_[slot].clear();
+            if (!receiveToCard(tls, buf + i, n - i, page, slot)) return;
+            tls.stop();
+            slotUrl_[slot] = url;
+            if (loadIntoRam) loadFromCard(page, freeBefore, slotPath(slot));
+            page.outcome = GeminiPage::Outcome::Ok;
+            return;
+        }
+        // Q86, two floors: once the connection closes, its ~50 KB comes back, so the page may use
+        // what was free before minus the steady floor; meanwhile the heap must stay above the
+        // transient floor. Both counted with the next 4 KB chunk and the line index.
+        size_t take = std::min<size_t>(n - i, kMaxBody - page.text.bytes());
+        size_t pageCost = page.text.bytes() + page.text.lineCount() * 8 + TextBuffer::kChunk + take;
+        if (take < static_cast<size_t>(n - i)) page.truncatedWhy = "longer than 64 KB";
+        else if (freeBefore < kSteadyFloor + pageCost) page.truncatedWhy = "not enough memory to keep it";
+        else if (esp_get_free_heap_size() < kTransientFloor + TextBuffer::kChunk + take)
+            page.truncatedWhy = "not enough memory while receiving";
+        if (!page.truncatedWhy.empty()) {
+            page.truncated = true;
+            break;
+        }
+        page.text.append(buf + i, take);
+        track();
+    }
+    if (cancel_) {
+        page.error = "Cancelled";
+        return;
+    }
+    if (!inBody && !gemini::parseHeader(header, page.header)) {  // a header with no line end
+        page.error = header.empty() ? "Empty response" : "Malformed response header";
+        return;
+    }
+    page.text.finish();
+    page.outcome = GeminiPage::Outcome::Ok;
+}
+
+// Streams the rest of the body to a cache file in 1 KB pieces, each written by the storage task:
+// with IRC's TLS connection and this one both open, every KB of RAM counts (Q86).
+
+bool GeminiService::receiveToCard(NetworkClientSecure& tls, const char* first, size_t len, GeminiPage& page, int slot) {
+    struct Cache {
+        File file;
+    };
+    auto cache = std::make_shared<Cache>();
+    bool opened = storage_.runAndWait([cache, slot]() {
+        SD.mkdir("/gemini");
+        SD.mkdir("/gemini/cache");
+        cache->file = SD.open(slotPath(slot), FILE_WRITE);
+    });
+    if (!opened || !cache->file) {
+        page.error = "Can't write to the SD card";
+        return false;
+    }
+    std::string pending(first, len);
+    constexpr size_t kPiece = 1024;
+    pending.reserve(kPiece + 512);
+    bool ok = true;
+    auto flush = [&]() {
+        if (pending.empty() || !ok) return;
+        ok = storage_.runAndWait([cache, &pending, &ok]() {
+            ok = cache->file.write(reinterpret_cast<const uint8_t*>(pending.data()), pending.size()) == pending.size();
+        }) && ok;
+        page.receivedBytes += pending.size();
+        pending.clear();
+    };
+    uint32_t last = millis();
+    char buf[512];
+    while (!cancel_ && ok) {
+        if (pending.size() >= kPiece) flush();
+        if (page.receivedBytes + pending.size() >= kMaxOnCard) {
+            page.truncated = true;
+            page.truncatedWhy = "longer than 1 MB";
+            break;
+        }
+        int n = tls.available() ? tls.read(reinterpret_cast<uint8_t*>(buf), sizeof buf) : 0;
+        if (n <= 0) {
+            if (!tls.connected()) break;
+            if (millis() - last > kIdleTimeoutMs) break;  // keep what came
+            delay(5);
+            continue;
+        }
+        last = millis();
+        pending.append(buf, n);
+        lowest_ = std::min<size_t>(lowest_, esp_get_free_heap_size());
+    }
+    flush();
+    storage_.runAndWait([cache]() { cache->file.close(); });
+    if (cancel_) page.error = "Cancelled";
+    else if (!ok) page.error = "Writing to the SD card failed";
+    else page.cachePath = slotPath(slot);
+    return !cancel_ && ok;
+}
+
+// Back into RAM, now that the connection's memory is free again: one pass over the file counts
+// its lines and indexes every kIndexEvery-th, and loads lines while the steady floor allows (Q86).
+// If they don't all fit, the page is windowed: the App asks for other windows as you scroll.
+void GeminiService::loadFromCard(GeminiPage& page, size_t freeBefore, const std::string& path) {
+    size_t budget = freeBefore > kSteadyFloor + TextBuffer::kChunk ? freeBefore - kSteadyFloor - TextBuffer::kChunk : 0;
+    budget = std::min(budget, kMaxBody);
+    page.backing = path;
+    page.lineIndex.clear();
+    page.totalLines = 0;
+    page.windowStart = 0;
+    bool loading = true;
+    storage_.runAndWait([&]() {
+        File f = SD.open(path.c_str());
+        if (!f) return;
+        std::string line;
+        uint32_t offset = 0, lineStart = 0;
+        bool pre = false;
+        auto endLine = [&]() {
+            if (page.totalLines % kIndexEvery == 0) page.lineIndex.push_back(lineStart | (pre ? 0x80000000u : 0));
+            if (line.compare(0, 3, "```") == 0) pre = !pre;
+            if (loading) {
+                if (page.text.bytes() + page.text.lineCount() * 8 + line.size() + 1 > budget) loading = false;
+                else {
+                    line += '\n';
+                    page.text.append(line.data(), line.size());
+                }
+            }
+            page.totalLines++;
+            line.clear();
+        };
+        char buf[512];
+        int n;
+        while ((n = f.read(reinterpret_cast<uint8_t*>(buf), sizeof buf)) > 0) {
+            for (int i = 0; i < n; i++, offset++) {
+                if (buf[i] == '\n') {
+                    endLine();
+                    lineStart = offset + 1;
+                } else if (line.size() < kMaxLineBytes) line += buf[i];
+            }
+        }
+        if (!line.empty()) endLine();
+        f.close();
+    });
+    page.text.finish();
+    page.windowed = !loading;
+    if (page.windowed)
+        console.printf("gemini: %s is windowed: %u of %u lines in memory\n", path.c_str(),
+                       (unsigned)page.text.lineCount(), (unsigned)page.totalLines);
+}
+
+// Lines from `firstLine` on, from the page's file, as many as `budget` allows.
+void GeminiService::readWindow(GeminiPage& page, size_t firstLine, size_t budget) {
+    size_t entry = firstLine / kIndexEvery;
+    if (entry >= page.lineIndex.size()) return;
+    storage_.runAndWait([&]() {
+        File f = SD.open(page.backing.c_str());
+        if (!f || !f.seek(page.lineIndex[entry] & 0x7FFFFFFFu)) return;
+        size_t lineNo = entry * kIndexEvery;
+        std::string line;
+        char buf[512];
+        int n;
+        bool done = false;
+        while (!done && (n = f.read(reinterpret_cast<uint8_t*>(buf), sizeof buf)) > 0) {
+            for (int i = 0; i < n && !done; i++) {
+                if (buf[i] != '\n') {
+                    if (line.size() < kMaxLineBytes) line += buf[i];
+                    continue;
+                }
+                if (lineNo >= firstLine) {
+                    if (page.text.bytes() + page.text.lineCount() * 8 + line.size() + 1 > budget) done = true;
+                    else {
+                        line += '\n';
+                        page.text.append(line.data(), line.size());
+                    }
+                }
+                lineNo++;
+                line.clear();
+            }
+        }
+        if (!done && !line.empty() && lineNo >= firstLine) page.text.append(line.data(), line.size());
+        f.close();
+    });
+    page.text.finish();
+}
+
+void GeminiService::report(const GeminiPage& page, size_t heapBefore, size_t heapLowest) {
+    console.printf("gemini: %s -> %s, %lu ms\n", page.requested.c_str(), page.url.c_str(), (unsigned long)page.ms);
+    if (page.outcome != GeminiPage::Outcome::Ok) console.printf("gemini: %s\n", page.error.c_str());
+    else console.printf("gemini: %d %s, %u bytes, %u lines%s\n", page.header.status, page.header.meta.c_str(),
+                        (unsigned)page.text.bytes(), (unsigned)page.text.lineCount(),
+                        page.truncated ? (" (truncated: " + page.truncatedWhy + ")").c_str() : "");
+    if (page.outcome == GeminiPage::Outcome::CertificateChanged)
+        console.printf("gemini: pinned %s\ngemini: now    %s\n", page.pinned.c_str(), page.presented.c_str());
+    for (size_t i = 0; i < page.text.lineCount() && i < 6; i++) console.printf("  %s\n", page.text.line(i).substr(0, 100).c_str());
+    if (!page.cachePath.empty())
+        console.printf("gemini: %u bytes on the card in %s\n", (unsigned)page.receivedBytes, page.cachePath.c_str());
+    console.printf("gemini: heap %u before, %u lowest seen, %u after\n", (unsigned)heapBefore, (unsigned)heapLowest,
+                   (unsigned)esp_get_free_heap_size());
+}
+
+
+}  // namespace roro

src/services/gemini_service.h

@@ -0,0 +1,143 @@
+#pragma once
+
+#include <freertos/FreeRTOS.h>
+#include <freertos/semphr.h>
+
+#include <string>
+#include <vector>
+
+#include "event_bus.h"
+#include "gemini_response.h"
+#include "key_value_store.h"
+#include "services/clock_service.h"
+#include "services/storage_service.h"
+#include "text_buffer.h"
+
+class NetworkClientSecure;
+
+namespace roro {
+
+// What a fetch came back with.
+struct GeminiPage {
+    enum class Outcome { Ok, Failed, CertificateChanged };
+    Outcome outcome = Outcome::Failed;
+    std::string requested;    // what was asked for
+    std::string url;          // where it ended up, after redirects (file://… for a Saved Page)
+    gemini::Header header;    // the final response's header
+    gemini::TextBuffer text;  // 2x only: the body as lines, up to kMaxBody
+    bool truncated = false;   // the body was cut: see truncatedWhy
+    std::string truncatedWhy;
+    std::string error;        // Failed: why, for a human
+    std::string host;         // CertificateChanged: whose, and both fingerprints
+    int port = 1965;
+    std::string pinned, presented;
+    std::string cachePath;    // with a card: the whole body as received (Saved Pages copy it)
+    size_t receivedBytes = 0; // the whole body, which may be more than `text` holds
+    std::string savedFrom;    // a Saved Page: the URL it was saved from (links resolve against it)
+    std::string savedOn;      // and when, "2026-10-05 01:20"
+    uint32_t ms = 0;
+    // A page bigger than memory allows is read from its file as you scroll: `text` then holds
+    // lines [windowStart, windowStart + text.lineCount()) of totalLines. lineIndex has where every
+    // 64th line starts in the file (bit 31: inside a preformatted block there).
+    std::string backing;      // the file the page is in (a cache file or a Saved Page)
+    bool windowed = false;
+    size_t totalLines = 0, windowStart = 0;
+    std::vector<uint32_t> lineIndex;
+    std::string windowOf;     // a window result: the backing file it belongs to
+
+    // What relative links resolve against.
+    const std::string& base() const { return savedFrom.empty() ? url : savedFrom; }
+};
+
+// Gemini (docs/milestones/G1.md). Everything that touches the network or the SD card runs as one
+// job at a time on a short-lived task of its own: a TLS handshake or a missing card can block for
+// seconds, which the main loop's watchdog wouldn't allow, and an idle client should cost no stack.
+// Certificates are trusted on first use, per host and port (Q71).
+class GeminiService {
+   public:
+    static constexpr size_t kMaxBody = 64 * 1024;        // Q74
+    static constexpr size_t kStartFloor = 55 * 1024;     // Q86: no fetch below this
+    static constexpr size_t kSteadyFloor = 40 * 1024;    // Q86: what must be left once the page is in
+    static constexpr size_t kTransientFloor = 20 * 1024; // Q86: while the TLS connection is open
+    static constexpr int kMaxRedirects = 5;              // Q72
+    static constexpr size_t kMaxOnCard = 1024 * 1024;    // a text page larger than this is cut
+    static constexpr int kMaxLinkedPages = 30;           // Q83
+    static constexpr size_t kIndexEvery = 64;            // lines between lineIndex entries
+    static constexpr size_t kMaxLineBytes = 8192;        // longer lines are cut
+    static constexpr const char* kBookmarks = "/gemini/bookmarks.gmi";
+    static constexpr const char* kStartUrl = "about:start";
+
+    GeminiService(KeyValueStore& store, StorageService& storage, ClockService& clock, EventBus& bus);
+
+    // Pages: gemini://…, about:start (bookmarks, Saved Pages, defaults) or file:///gemini/saved/….
+    // `preferSaved`: open the Saved Page of that URL if there is one (inside a Saved Page, Q84).
+    bool fetch(const std::string& url, bool preferSaved = false);
+    // Actions; each reports one line through takeMessage().
+    bool save(const std::string& url);                                  // s (Q82)
+    bool saveWithLinks(const std::string& url, std::vector<std::string> links);  // S (Q83)
+    bool refresh(const std::string& savedPath);                         // r on a Saved Page
+    bool deleteSaved(const std::string& savedPath);                     // d on a Saved Page (Q85)
+    bool addBookmark(const std::string& url, const std::string& title); // b (Q77)
+    bool download(const std::string& url);                              // s on a non-text page (Q73)
+    // The window of a big page starting at `firstLine` (a multiple of kIndexEvery), from its file.
+    bool loadWindow(const GeminiPage& page, size_t firstLine);
+
+    bool busy() const { return busy_; }
+    bool takeResult(GeminiPage& out);
+    bool takeMessage(std::string& out);
+    void cancel() { cancel_ = true; }
+    // After the user accepts a changed certificate.
+    void trust(const std::string& host, int port, const std::string& fingerprint);
+
+    // `gemini get <url>`: the same fetch, reported on the console instead of to the App.
+    bool fetchToConsole(const std::string& url);
+
+   private:
+    enum class Job { Fetch, Save, SaveWithLinks, Refresh, Delete, Bookmark, Download, Window };
+    // Cache files: two take turns for pages on screen (the one shown is never overwritten by the
+    // next), one for jobs (saving linked pages, refreshing).
+    static constexpr int kWorkSlot = 2;
+    static const char* slotPath(int slot);
+
+    bool start(Job job);
+    static void taskEntry(void* self);
+    void run();
+    void runFetch(GeminiPage& page);
+    void fetchFollowing(const std::string& url, GeminiPage& page, bool loadIntoRam, int slot);
+    void fetchOne(const std::string& url, GeminiPage& page, bool loadIntoRam, int slot);
+    bool receiveToCard(::NetworkClientSecure& tls, const char* first, size_t len, GeminiPage& page, int slot);
+    void loadFromCard(GeminiPage& page, size_t freeBefore, const std::string& path);
+    void readWindow(GeminiPage& page, size_t firstLine, size_t budget);
+    void openSaved(const std::string& path, GeminiPage& page);
+    std::string savedFirstLine(const std::string& path);
+    std::string savedFrom(const std::string& path);
+    void composeStart(GeminiPage& page);
+    std::string saveCached(const std::string& url);  // "" or what went wrong
+    const char* cacheOf(const std::string& url) const;  // the cache file holding url's body, or nullptr
+    void finishWithMessage(const std::string& text);
+    void notify(const std::string& text);
+    void report(const GeminiPage& page, size_t heapBefore, size_t heapLowest);
+    std::string pinKey(const std::string& host, int port) const;
+    std::string now() const;
+
+    KeyValueStore& store_;
+    StorageService& storage_;
+    ClockService& clock_;
+    EventBus& bus_;
+    SemaphoreHandle_t lock_;
+    Job job_ = Job::Fetch;
+    std::string arg_, arg2_;
+    std::vector<std::string> links_;
+    bool preferSaved_ = false;
+    GeminiPage result_;
+    std::string message_;
+    std::string slotUrl_[3];  // the URL whose body each cache file holds
+    int nextDisplay_ = 0;
+    size_t windowLine_ = 0, windowReleasing_ = 0;
+    GeminiPage windowPage_;
+    bool replaced_ = false;  // the last save replaced an older copy
+    volatile bool busy_ = false, ready_ = false, messageReady_ = false, cancel_ = false, toConsole_ = false;
+    size_t lowest_ = 0;
+};
+
+}  // namespace roro

src/services/gnss_service.cpp

@@ -0,0 +1,203 @@
+#include "services/gnss_service.h"
+
+#include <Arduino.h>
+#include <SD.h>
+
+#include <algorithm>
+#include <cstdio>
+
+#include "platform/console.h"
+
+namespace roro {
+
+namespace {
+const char* fixName(gnss::FixType f) {
+    return f == gnss::FixType::ThreeD ? "3D" : f == gnss::FixType::TwoD ? "2D" : "none";
+}
+}  // namespace
+
+GnssService::GnssService(const Settings& settings, ClockService& clock, StorageService& storage, EventBus& bus)
+    : settings_(settings), clock_(clock), storage_(storage), bus_(bus) {
+    parser_.onLine = [this](const std::string& line) {
+        lastLineMs_ = millis();
+        if (echo_) console.printf("nmea: %s\n", line.c_str());
+    };
+}
+
+void GnssService::start() {
+    open(millis());
+    storage_.runJob([this]() { closeUnfinishedTracks(); });
+}
+
+void GnssService::stop() { close(); }
+
+void GnssService::open(uint32_t nowMs) {
+    Serial1.setRxBufferSize(512);  // before begin(): over a second of NMEA, read every 50 ms
+    Serial1.begin(kBaud, SERIAL_8N1, kRxPin, kTxPin);
+    open_ = true;
+    active_ = false;  // tick() wakes it or puts it to sleep, per the setting
+    standbyMs_ = 0;
+}
+
+void GnssService::wake(uint32_t nowMs) {
+    send("PCAS10,0");  // hot start: ends a standby, keeps what the receiver knows
+    active_ = true;
+    openedMs_ = nowMs;
+    firstFixMs_ = 0;
+    lastLineMs_ = 0;
+    lastFix_ = gnss::FixType::None;
+    console.println("gnss: on");
+}
+
+void GnssService::standby(uint32_t nowMs) {
+    if (tracking()) stopTrack();
+    send("PCAS12,65535");
+    if (active_) console.println("gnss: off (receiver in standby)");
+    active_ = false;
+    standbyMs_ = nowMs;
+}
+
+void GnssService::close() {
+    if (!open_) return;
+    Serial1.end();
+    open_ = active_ = false;
+    lastLineMs_ = 0;
+}
+
+void GnssService::tick(uint32_t nowMs) {
+    if (!open_) open(nowMs);
+    bool wanted = settings_.getBool(Setting::GnssEnabled);
+    if (wanted && !active_) wake(nowMs);
+    if (!wanted && (active_ || !standbyMs_ || nowMs - standbyMs_ >= kStandbyRenewMs)) standby(nowMs);
+
+    char buf[128];
+    for (int avail; (avail = Serial1.available()) > 0;) {
+        size_t n = Serial1.read(reinterpret_cast<uint8_t*>(buf), std::min<size_t>(avail, sizeof buf));
+        if (n == 0) break;
+        bytes_ += n;
+        if (active_) parser_.feed(buf, n);  // in standby: the last lines before it, discarded
+    }
+
+    if (!active_) return;
+    const gnss::GnssState& s = parser_.state();
+    if (s.fix != lastFix_) {
+        if (s.fix != gnss::FixType::None && !firstFixMs_) {
+            firstFixMs_ = nowMs - openedMs_;
+            console.printf("gnss: first Fix after %lu s\n", (unsigned long)(firstFixMs_ / 1000));
+        }
+        console.printf("gnss: Fix %s, %d satellites used\n", fixName(s.fix), s.satellitesUsed);
+        lastFix_ = s.fix;
+    }
+    recordPoint(nowMs);
+    // GNSS time is the most trusted source (ClockModel): set it with a Fix, then now and then.
+    if (s.timeValid && s.fix != gnss::FixType::None && (!clockSetMs_ || nowMs - clockSetMs_ >= kClockEveryMs)) {
+        if (clock_.set(s.utcSeconds(), TimeSource::Gnss) && !clockSetMs_) console.println("gnss: clock set");
+        clockSetMs_ = nowMs;
+    }
+}
+
+void GnssService::notify(const std::string& text) {
+    bus_.publish(Event::withText(EventType::Notification, text.c_str(), static_cast<int32_t>(NotificationLevel::Info)));
+}
+
+std::string GnssService::startTrack(uint32_t nowMs) {
+    if (tracking()) return "";
+    if (!active_) return "GNSS is off";
+    if (!storage_.state().present) return "No SD card";
+    int64_t now = clock_.utcNow();
+    if (now < 0) return "Waiting for the time (a Fix or Wi-Fi)";
+    trackPath_ = gnss::trackPath(now);
+    std::string name = trackPath_.substr(trackPath_.rfind('/') + 1);
+    name = name.substr(0, name.size() - 4);  // without ".gpx"
+    storage_.appendLine(trackPath_, gnss::gpx::header(name), true);
+    trackPoints_ = 0;
+    trackStartMs_ = nowMs;
+    trackRule_.reset();
+    console.printf("gnss: Track %s started\n", trackPath_.c_str());
+    notify("Track started");
+    return "";
+}
+
+void GnssService::stopTrack() {
+    if (!tracking()) return;
+    storage_.appendLine(trackPath_, gnss::gpx::footer(), true);
+    console.printf("gnss: Track %s saved, %d points\n", trackPath_.c_str(), trackPoints_);
+    notify("Track saved: " + std::to_string(trackPoints_) + (trackPoints_ == 1 ? " point" : " points"));
+    trackPath_.clear();
+}
+
+void GnssService::recordPoint(uint32_t nowMs) {
+    const gnss::GnssState& s = parser_.state();
+    if (!tracking() || !s.positionValid || !s.timeValid) return;
+    if (!trackRule_.due(nowMs, s.latitude, s.longitude)) return;
+    storage_.appendLine(trackPath_,
+                        gnss::gpx::point(s.latitude, s.longitude, s.altitudeValid, s.altitudeM, s.utcSeconds()), true);
+    trackPoints_++;
+}
+
+// A Track cut short by a power loss or a crash has no footer: GPX readers refuse it. Close it.
+void GnssService::closeUnfinishedTracks() {
+    File dir = SD.open("/gnss/tracks");
+    if (!dir || !dir.isDirectory()) return;
+    int closed = 0;
+    for (File f = dir.openNextFile(); f; f = dir.openNextFile()) {
+        std::string name = f.name();
+        if (f.isDirectory() || name.size() < 4 || name.compare(name.size() - 4, 4, ".gpx") != 0) continue;
+        char tail[32] = {};
+        size_t size = f.size();
+        f.seek(size > sizeof tail - 1 ? size - (sizeof tail - 1) : 0);
+        f.read(reinterpret_cast<uint8_t*>(tail), sizeof tail - 1);
+        f.close();
+        if (gnss::gpx::finished(tail)) continue;
+        File out = SD.open(("/gnss/tracks/" + name).c_str(), FILE_APPEND);
+        if (out) {
+            out.print(("\n" + gnss::gpx::footer() + "\n").c_str());
+            out.close();
+            closed++;
+        }
+    }
+    if (closed) console.printf("gnss: closed %d unfinished Track(s)\n", closed);
+}
+
+bool GnssService::send(const std::string& body) {
+    if (!open_) return false;
+    uint8_t sum = 0;
+    for (char c : body) sum ^= static_cast<uint8_t>(c);
+    char tail[8];
+    std::snprintf(tail, sizeof tail, "*%02X\r\n", sum);
+    std::string line = "$" + body + tail;
+    Serial1.write(reinterpret_cast<const uint8_t*>(line.data()), line.size());
+    return true;
+}
+
+void GnssService::printStatus(Print& out, uint32_t nowMs) const {
+    if (!active_) return (void)out.println("gnss: off (receiver in standby)");
+    const gnss::GnssState& s = parser_.state();
+    out.printf("gnss: %s, Fix %s, %d used, %u in view, HDOP %.1f\n",
+               receiving(nowMs) ? "receiving" : "silent", fixName(s.fix), s.satellitesUsed,
+               (unsigned)s.satellites.size(), s.hdop);
+    if (s.positionValid)
+        out.printf("gnss: %.6f %.6f, %s%.0f m, %.1f km/h\n", s.latitude, s.longitude,
+                   s.altitudeValid ? "" : "altitude unknown ", s.altitudeM, s.speedKmh);
+    if (s.timeValid)
+        out.printf("gnss: %04d-%02d-%02d %02d:%02d:%02d UTC\n", s.year, s.month, s.day, s.hour, s.minute, s.second);
+    int perSystem[8] = {}, usedPerSystem[8] = {};
+    for (auto& sat : s.satellites) {
+        perSystem[static_cast<int>(sat.system)]++;
+        if (sat.used) usedPerSystem[static_cast<int>(sat.system)]++;
+    }
+    out.print("gnss: in view (used)");
+    for (int c = 1; c < 7; c++)
+        if (perSystem[c])
+            out.printf(" %s %d (%d)", gnss::constellationName(static_cast<gnss::Constellation>(c)), perSystem[c],
+                       usedPerSystem[c]);
+    out.println();
+    if (tracking())
+        out.printf("gnss: recording %s, %d points, %lu s\n", trackPath_.c_str(), trackPoints_,
+                   (unsigned long)((nowMs - trackStartMs_) / 1000));
+    out.printf("gnss: up %lu s, first Fix %s, %lu bytes, %lu sentences, %lu bad\n", (unsigned long)((nowMs - openedMs_) / 1000),
+               firstFixMs_ ? (std::to_string(firstFixMs_ / 1000) + " s").c_str() : "not yet", (unsigned long)bytes_,
+               (unsigned long)parser_.goodSentences(), (unsigned long)parser_.badSentences());
+}
+
+}  // namespace roro

src/services/gnss_service.h

@@ -0,0 +1,84 @@
+#pragma once
+
+#include <Print.h>
+
+#include <string>
+
+#include "event_bus.h"
+#include "nmea_parser.h"
+#include "service.h"
+#include "services/clock_service.h"
+#include "services/storage_service.h"
+#include "settings.h"
+#include "track.h"
+
+namespace roro {
+
+// The GNSS receiver on the Cap LoRa-1262 (see CONTEXT.md and docs/milestones/M2.md): reads its
+// NMEA from the main loop's tick (about 450 bytes/s, so a 512-byte UART buffer covers a second),
+// holds the current Fix, and sets the clock from it. Settings → GNSS switches it on and off.
+class GnssService : public Service {
+   public:
+    static constexpr int kRxPin = 15, kTxPin = 13;  // measured: M2 step 1
+    static constexpr uint32_t kBaud = 115200;
+    static constexpr uint32_t kSilentAfterMs = 3000;  // no sentence for this long: receiver silent
+    static constexpr uint32_t kClockEveryMs = 600000; // refresh the clock from the Fix this often
+    // Off (Q58, measured): "$PCAS12,<s>" puts the receiver in standby for that long, and any
+    // command wakes it. Standby is renewed while off, in case the duration is clamped.
+    static constexpr uint32_t kStandbyRenewMs = 3600000;
+
+    GnssService(const Settings& settings, ClockService& clock, StorageService& storage, EventBus& bus);
+    const char* name() const override { return "gnss"; }
+    uint32_t tickIntervalMs() const override { return 50; }
+    void start() override;
+    void stop() override;
+    void tick(uint32_t nowMs) override;
+
+    bool on() const { return active_; }
+    bool receiving(uint32_t nowMs) const { return active_ && lastLineMs_ && nowMs - lastLineMs_ < kSilentAfterMs; }
+    const gnss::GnssState& state() const { return parser_.state(); }
+    uint32_t onSinceMs() const { return openedMs_; }  // when the receiver was last woken
+
+    // Debug aids (Q68): raw sentences to the console, a status report, and sending a command
+    // ("PCAS10,0" becomes "$PCAS10,0*1C\r\n").
+    void setEcho(bool echo) { echo_ = echo; }
+    void printStatus(Print& out, uint32_t nowMs) const;
+    bool send(const std::string& body);
+    // Tracks (Q63): GPX on the SD card, a point every 5 s once moved 5 m, recorded in the
+    // background whatever App is open. startTrack() returns why it can't, or "".
+    std::string startTrack(uint32_t nowMs);
+    void stopTrack();
+    bool tracking() const { return !trackPath_.empty(); }
+    int trackPoints() const { return trackPoints_; }
+    uint32_t trackStartMs() const { return trackStartMs_; }
+
+    void restart(uint32_t nowMs) {
+        close();
+        open(nowMs);
+    }
+
+   private:
+    void open(uint32_t nowMs);  // the UART; the receiver's state follows the setting in tick()
+    void close();
+    void wake(uint32_t nowMs);
+    void recordPoint(uint32_t nowMs);
+    void closeUnfinishedTracks();  // on the storage task
+    void notify(const std::string& text);
+    void standby(uint32_t nowMs);
+
+    const Settings& settings_;
+    ClockService& clock_;
+    StorageService& storage_;
+    EventBus& bus_;
+    gnss::NmeaParser parser_;
+    bool open_ = false, active_ = false, echo_ = false;
+    uint32_t bytes_ = 0, standbyMs_ = 0;
+    uint32_t openedMs_ = 0, lastLineMs_ = 0, firstFixMs_ = 0, clockSetMs_ = 0;
+    gnss::FixType lastFix_ = gnss::FixType::None;
+    std::string trackPath_;
+    int trackPoints_ = 0;
+    uint32_t trackStartMs_ = 0;
+    gnss::TrackRule trackRule_;
+};
+
+}  // namespace roro

src/services/irc_service.cpp

@@ -33,16 +33,23 @@ IrcService::IrcService(KeyValueStore& store, const std::string& defaultNick, Wif
 void IrcService::start() {
     if (task_) return;
     lock_ = xSemaphoreCreateMutex();
-    xTaskCreate(taskEntry, "irc", 8192, this, 1, &task_);
+    xTaskCreate(taskEntry, "irc", 6144, this, 1, &task_);  // peak 4.0 KB (TLS handshake, M2)
 }
 
 void IrcService::connect() {
+    stoppedByUser_ = false;
     if (wanted_) return;
     retryAtMs_ = millis();
     backoff_.reset();
     wanted_ = true;
 }
 
+void IrcService::disconnect() {
+    stoppedByUser_ = true;
+    stopRequested_ = true;  // the IRC task says QUIT and closes; nothing to do if it never started
+    if (!task_) wanted_ = false;
+}
+
 int IrcService::totalUnread() {
     Lock l(lock_);
     return session_->totalUnread();
@@ -176,13 +183,10 @@ void IrcService::flushEffects() {
         status_ = Status::Online;
         backoff_.reset();
     }
-    if (quit && open_) {
+    if (quit) {  // /quit: QUIT is already on its way if connected; stop in any state
-        delay(300);  // let QUIT reach the server
+        stoppedByUser_ = true;
-        close("");
+        stopRequested_ = true;
-        wanted_ = false;
+        quitSent_ = true;
-        status_ = Status::Stopped;
-        Lock l(lock_);
-        session_->disconnected(clock_.utcNow(), "disconnected");
     }
 }
 
@@ -192,6 +196,19 @@ void IrcService::loop() {
         bool wifiUp = wifi_.state() == WifiController::State::Connected;
         bool monitoring = wifi_.state() == WifiController::State::Monitoring;
 
+        if (stopRequested_) {
+            stopRequested_ = false;
+            if (open_) {
+                if (!quitSent_) conn_->print("QUIT :roro9stack\r\n");
+                vTaskDelay(pdMS_TO_TICKS(300));  // let QUIT reach the server
+                close("");
+            }
+            quitSent_ = false;
+            wanted_ = false;
+            status_ = Status::Stopped;
+            Lock l(lock_);
+            session_->disconnected(clock_.utcNow(), "disconnected (Enter reconnects)");
+        }
         if (restart_) {
             restart_ = false;
             if (open_) {

src/services/irc_service.h

@@ -31,9 +31,12 @@ class IrcService : public Service {
     const char* name() const override { return "irc"; }
     void start() override;
 
-    // Starts the session (the IRC App does this when opened); /quit stops it.
+    // Starts the session (the IRC App does this when opened, unless you stopped it).
     void connect();
+    // Stops it, from any state: says QUIT if connected, and stops retrying. /quit, `irc stop`.
+    void disconnect();
     bool running() const { return wanted_; }
+    bool stoppedByUser() const { return stoppedByUser_; }
     Status status() const { return status_; }
 
     // Read or act on the session while holding its lock: withSession([](IrcSession& s) { ... }).
@@ -78,6 +81,9 @@ class IrcService : public Service {
     ReconnectPolicy backoff_;
     std::string partial_;
     volatile bool wanted_ = false;
+    volatile bool stoppedByUser_ = false;  // a manual stop: opening the App doesn't reconnect
+    volatile bool stopRequested_ = false;
+    bool quitSent_ = false;  // /quit already queued its QUIT
     volatile bool restart_ = false;
     volatile Status status_ = Status::Stopped;
     bool open_ = false;

src/services/storage_service.cpp

@@ -5,6 +5,7 @@
 #include <sd_diskio.h>
 
 #include <algorithm>
+#include <atomic>
 #include <memory>
 
 #include "platform/pins.h"
@@ -14,8 +15,7 @@ namespace roro {
 
 void StorageService::start() {
     if (task_) return;
-    lock_ = xSemaphoreCreateMutex();
+    xTaskCreate(taskEntry, "storage", 6144, this, 1, &task_);  // peak 3.9 KB (SD install with its signature check, M2)
-    xTaskCreate(taskEntry, "storage", 6144, this, 1, &task_);
 }
 
 void StorageService::stop() {
@@ -33,10 +33,11 @@ StorageState StorageService::state() const {
     return copy;
 }
 
-void StorageService::appendLine(const std::string& path, const std::string& line) {
+void StorageService::appendLine(const std::string& path, const std::string& line, bool capture) {
     lock();
     size_t bytes = path.size() + line.size();
-    bool accept = monitor_.state().logsAllowed && pendingBytes_ + bytes <= kMaxPendingBytes;
+    bool allowed = capture ? monitor_.state().capturesAllowed : monitor_.state().logsAllowed;
+    bool accept = allowed && pendingBytes_ + bytes <= kMaxPendingBytes;
     if (accept) {
         pending_.emplace_back(path, line);
         pendingBytes_ += bytes;
@@ -75,6 +76,37 @@ void StorageService::requestDelete(std::vector<std::string> paths) {
     if (task_) xTaskNotifyGive(task_);
 }
 
+void StorageService::runJob(std::function<void()> job) {
+    lock();
+    jobs_.push_back(std::move(job));
+    unlock();
+    if (task_) xTaskNotifyGive(task_);
+}
+
+bool StorageService::runAndWait(std::function<void()> job) {
+    // Shared with the job, which outlives this wait if the card is missing and it never starts.
+    // Exactly one side wins the state change: the job (Queued -> Running) or the wait giving up
+    // (Queued -> Abandoned), so an abandoned job can never touch this stack frame.
+    enum : int { Queued, Running, Abandoned };
+    struct Run {
+        std::atomic<int> state{Queued};
+        SemaphoreHandle_t done = xSemaphoreCreateBinary();
+        ~Run() { vSemaphoreDelete(done); }
+    };
+    auto run = std::make_shared<Run>();
+    runJob([run, job]() {
+        int expected = Queued;
+        if (!run->state.compare_exchange_strong(expected, Running)) return;
+        job();
+        xSemaphoreGive(run->done);
+    });
+    for (int waited = 0; xSemaphoreTake(run->done, pdMS_TO_TICKS(500)) != pdTRUE; waited += 500) {
+        int expected = Queued;
+        if (waited >= 5000 && run->state.compare_exchange_strong(expected, Abandoned)) return false;
+    }
+    return true;
+}
+
 bool StorageService::requestFormat() {
     if (formatRequested_ || !task_) return false;
     formatRequested_ = true;
@@ -109,6 +141,13 @@ void StorageService::loop() {
         }
         if (wantListing) list();
 
+        lock();
+        std::vector<std::function<void()>> jobs;
+        jobs.swap(jobs_);
+        unlock();
+        for (auto& job : jobs)
+            if (mounted_) job();
+
         // Sleep until the next batch, or until a request wakes us early.
         ulTaskNotifyTake(pdTRUE, pdMS_TO_TICKS(kWakeMs));
     }

src/services/storage_service.h

@@ -4,6 +4,7 @@
 #include <freertos/semphr.h>
 
 #include <deque>
+#include <functional>
 #include <string>
 #include <utility>
 #include <vector>
@@ -19,7 +20,8 @@ namespace roro {
 // queued Log lines in batches, lists files for Storage Clean-up, deletes, and formats.
 class StorageService : public Service {
    public:
-    explicit StorageService(EventBus& bus) : monitor_(bus), bus_(bus) {}
+    // The lock exists from the start, so a Service that's never started (Safe Mode) can still be asked.
+    explicit StorageService(EventBus& bus) : monitor_(bus), bus_(bus), lock_(xSemaphoreCreateMutex()) {}
     const char* name() const override { return "storage"; }
     void start() override;
     void stop() override;
@@ -27,8 +29,9 @@ class StorageService : public Service {
     StorageState state() const;
 
     // Queues one line for a Log file (created with its folders as needed). Dropped while Logs are
-    // paused (over 90 % full, or no card) or if too much is already waiting.
+    // paused (over 90 % full, or no card) or if too much is already waiting. A Capture (or a Track,
-    void appendLine(const std::string& path, const std::string& line);
+    // something the user started) keeps going past 90 %, until the card is full.
+    void appendLine(const std::string& path, const std::string& line, bool capture = false);
     uint32_t droppedLines() const { return dropped_; }
 
     // Storage Clean-up: list every file of every category, then delete a selection.
@@ -37,6 +40,12 @@ class StorageService : public Service {
     std::vector<std::vector<StoredFile>> listing() const;  // one vector per kCleanupCategories entry
     void requestDelete(std::vector<std::string> paths);
 
+    // Runs `job` on the storage task, where card access is safe (e.g. reading an Update File).
+    void runJob(std::function<void()> job);
+    // The same, and waits for it (from another task, never the storage task itself). False if it
+    // never started within 5 s: no card mounted, and then it never will run.
+    bool runAndWait(std::function<void()> job);
+
     // Erases the whole card: one partition spanning the card, formatted FAT32.
     bool requestFormat();
     bool formatting() const { return formatRequested_; }
@@ -71,6 +80,7 @@ class StorageService : public Service {
     bool listingReady_ = false;
     std::vector<std::vector<StoredFile>> listing_;
     std::vector<std::string> toDelete_;
+    std::vector<std::function<void()>> jobs_;
     volatile bool formatRequested_ = false;
 };
 

src/services/update_service.cpp

@@ -0,0 +1,224 @@
+#include "update_service.h"
+
+#include <SD.h>
+#include <WiFi.h>
+#include <esp_ota_ops.h>
+
+#include <memory>
+
+#include "platform/ota_device.h"
+#include "platform/system_info.h"
+#include "probation.h"
+#include "update_parser.h"
+#include "version.h"
+
+namespace roro {
+
+// Where an Update File comes from: the network or a file on the SD card.
+class UpdateSource {
+   public:
+    virtual ~UpdateSource() = default;
+    // Bytes read, 0 at the end of the file, -1 on an error or a stall.
+    virtual int read(uint8_t* buf, size_t len) = 0;
+    virtual void reply(const std::string& line) { (void)line; }
+};
+
+namespace {
+
+constexpr uint32_t kStallMs = 10000;
+constexpr uint32_t kForceRestartMs = 90000;  // the main loop waits up to 60 s for someone typing
+constexpr size_t kChunk = 4096;
+
+class NetSource : public UpdateSource {
+   public:
+    explicit NetSource(NetworkClient& c) : c_(c) {}
+    int read(uint8_t* buf, size_t len) override {
+        uint32_t since = millis();
+        while (!c_.available()) {
+            if (!c_.connected()) return 0;  // the sender closed its side: end of file
+            if (millis() - since > kStallMs) return -1;
+            delay(5);
+        }
+        return c_.read(buf, len);
+    }
+    void reply(const std::string& line) override {
+        c_.print((line + "\n").c_str());
+        c_.flush();
+    }
+
+   private:
+    NetworkClient& c_;
+};
+
+class FileSource : public UpdateSource {
+   public:
+    explicit FileSource(File& f) : f_(f) {}
+    int read(uint8_t* buf, size_t len) override { return static_cast<int>(f_.read(buf, len)); }
+
+   private:
+    File& f_;
+};
+
+}  // namespace
+
+UpdateService::UpdateService(KeyValueStore& store, WifiService& wifi, SavedNetworks& saved, StorageService& storage,
+                             EventBus& bus, const Settings& settings)
+    : store_(store), wifi_(wifi), saved_(saved), storage_(storage), bus_(bus), settings_(settings) {
+}
+
+void UpdateService::notify(const std::string& text, NotificationLevel level) {
+    bus_.publish(Event::withText(EventType::Notification, text.c_str(), static_cast<int32_t>(level)));
+}
+
+std::string UpdateService::incomingVersion() const { return incoming_; }
+
+void UpdateService::start() {
+    // Probation: new firmware boots "pending verify" until it marks itself valid.
+    esp_ota_img_states_t state;
+    probation_ = esp_ota_get_state_partition(esp_ota_get_running_partition(), &state) == ESP_OK &&
+                 state == ESP_OTA_IMG_PENDING_VERIFY;
+
+    // A pending update that isn't the running version means the bootloader rolled it back.
+    std::string pending, from;
+    store_.getString("ota_pending", pending);
+    store_.getString("ota_from", from);
+    if (!pending.empty() && pending != versionString()) {
+        notify("Update to " + pending + " failed, back on " + versionString(), NotificationLevel::Warning);
+        store_.putString("ota_pending", "");
+    }
+
+    if (!task_) xTaskCreate(taskEntry, "update", 5120, this, 1, &task_);  // peak 3.4 KB (ECDSA check, M2)
+}
+
+void UpdateService::bootGuard(KeyValueStore& store) {
+    esp_ota_img_states_t state;
+    bool probation = esp_ota_get_state_partition(esp_ota_get_running_partition(), &state) == ESP_OK &&
+                     state == ESP_OTA_IMG_PENDING_VERIFY;
+    system_info::recordSlotVersion(store, esp_ota_get_running_partition(), versionString());
+    int32_t attempts = 0;
+    store.getInt("ota_attempts", attempts);
+    if (Probation::rollBackAtBoot(probation, attempts)) {
+        store.putInt("ota_attempts", 0);
+        esp_ota_mark_app_invalid_rollback_and_reboot();  // does not return when there's a previous image
+    }
+    store.putInt("ota_attempts", probation ? attempts + 1 : 0);
+}
+
+void UpdateService::tick(uint32_t nowMs) {
+    if (!probation_) return;
+    bool wifiConfigured = settings_.getBool(Setting::WifiEnabled) && saved_.count() > 0;
+    bool wifiUp = wifi_.state() == WifiController::State::Connected;
+    switch (Probation::judge(nowMs, firstFrame_, wifiConfigured, wifiUp)) {
+        case Probation::Verdict::Wait: break;
+        case Probation::Verdict::Confirm:
+            esp_ota_mark_app_valid_cancel_rollback();
+            probation_ = false;
+            store_.putString("ota_pending", "");
+            store_.putInt("ota_attempts", 0);
+            notify(std::string("Updated to ") + versionString(), NotificationLevel::Info);
+            break;
+        case Probation::Verdict::RollBack:
+            // ota_pending still names this version: the previous firmware will report the failure.
+            store_.putInt("ota_attempts", 0);
+            delay(200);
+            esp_ota_mark_app_invalid_rollback_and_reboot();
+            break;
+    }
+}
+
+void UpdateService::install(UpdateSource& source, const char* via) {
+    EcdsaVerifier verifier;
+    EspOtaSink sink;
+    UpdateParser parser(verifier, sink, sink.capacity(), versionString());
+    std::unique_ptr<uint8_t[]> buf(new uint8_t[kChunk]);
+    incoming_.clear();
+    percent_ = 0;
+    phase_ = Phase::Receiving;
+
+    bool ok = false;
+    for (;;) {
+        int n = source.read(buf.get(), kChunk);
+        if (n < 0) break;  // stalled or broken: aborted below
+        if (n == 0) {
+            ok = parser.end();
+            break;
+        }
+        parser.feed(buf.get(), n);
+        if (incoming_.empty() && parser.state() == UpdateParser::State::Image) incoming_ = parser.version();
+        percent_ = parser.percent();
+        if (parser.state() == UpdateParser::State::Failed) break;
+        if (parser.complete()) {  // all announced bytes are here: answer while the connection is open
+            ok = parser.end();
+            break;
+        }
+    }
+    if (!ok && parser.error().empty()) parser.end();  // e.g. a stall: abort the slot
+
+    if (ok) {
+        store_.putString("ota_pending", parser.version());
+        system_info::recordSlotVersion(store_, esp_ota_get_boot_partition(), parser.version().c_str());
+        store_.putString("ota_from", versionString());
+        source.reply("OK " + parser.version() + (parser.isDowngrade() ? " (older than the installed one)" : ""));
+        notify("Update " + parser.version() + " installed (" + via + "), restarting", NotificationLevel::Info);
+        phase_ = Phase::Installed;
+    } else {
+        std::string why = parser.error().empty() ? "transfer interrupted" : parser.error();
+        source.reply("ERR " + why);
+        notify("Update refused: " + why, NotificationLevel::Warning);
+        phase_ = Phase::Idle;
+    }
+}
+
+void UpdateService::installFromSd(const std::string& path) {
+    if (phase_ != Phase::Idle) return;
+    storage_.runJob([this, path]() {
+        File f = SD.open(path.c_str());
+        if (!f) {
+            notify("Can't open " + path, NotificationLevel::Warning);
+            return;
+        }
+        FileSource src(f);
+        install(src, "SD card");
+        f.close();
+    });
+}
+
+void UpdateService::taskEntry(void* self) { static_cast<UpdateService*>(self)->listen(); }
+
+void UpdateService::listen() {
+    NetworkServer server(kPort);
+    bool listening = false;
+    uint32_t installedAt = 0;
+    for (;;) {
+        bool connected = wifi_.state() == WifiController::State::Connected;
+        if (connected && !listening) {
+            server.begin();
+            listening = true;
+        } else if (!connected && listening) {
+            server.end();
+            listening = false;
+        }
+        // The main loop restarts into an installed update when it's safe. If it never does (stuck,
+        // or waiting on someone typing for too long), restart from here: the update must not wait.
+        if (phase_ == Phase::Installed) {
+            if (!installedAt) installedAt = millis();
+            if (millis() - installedAt > kForceRestartMs) {
+                ESP_LOGW("update", "the main loop never restarted into the update: restarting");
+                esp_restart();
+            }
+        }
+        if (listening && phase_ == Phase::Idle) {
+            NetworkClient client = server.accept();
+            if (client) {
+                client.setNoDelay(true);
+                NetSource src(client);
+                install(src, "Wi-Fi");
+                delay(50);
+                client.stop();
+            }
+        }
+        vTaskDelay(pdMS_TO_TICKS(200));
+    }
+}
+
+}  // namespace roro

src/services/update_service.h

@@ -0,0 +1,67 @@
+#pragma once
+
+#include <freertos/FreeRTOS.h>
+
+#include <string>
+
+#include "event_bus.h"
+#include "key_value_store.h"
+#include "service.h"
+#include "services/storage_service.h"
+#include "services/wifi_service.h"
+
+namespace roro {
+
+// Firmware Updates (see CONTEXT.md and docs/milestones/OTA.md): listens for signed Update Files on
+// TCP 3232 while Wi-Fi is Connected, installs them from the SD card on request, keeps new firmware
+// on Probation until it proves healthy, and reports a Rollback after the reboot.
+class UpdateService : public Service {
+   public:
+    enum class Phase { Idle, Receiving, Installed, Failed };
+    static constexpr uint16_t kPort = 3232;
+
+    // Call first in setup(): rolls back new firmware that already died once on Probation.
+    static void bootGuard(KeyValueStore& store);
+
+    UpdateService(KeyValueStore& store, WifiService& wifi, SavedNetworks& saved, StorageService& storage,
+                  EventBus& bus, const Settings& settings);
+    const char* name() const override { return "update"; }
+    uint32_t tickIntervalMs() const override { return 1000; }
+    void start() override;
+    void tick(uint32_t nowMs) override;
+
+    // For the progress screen and the Firmware page.
+    Phase phase() const { return phase_; }
+    int percent() const { return percent_; }
+    std::string incomingVersion() const;
+    bool onProbation() const { return probation_; }
+
+    // Installs an Update File from the SD card (runs on the storage task).
+    void installFromSd(const std::string& path);
+
+    // The main loop calls this once it has drawn a frame (part of Probation).
+    void firstFrameDrawn() { firstFrame_ = true; }
+    // True when an installed update is waiting to reboot; the main loop reboots when it's safe.
+    bool rebootPending() const { return phase_ == Phase::Installed; }
+
+   private:
+    static void taskEntry(void* self);
+    void listen();
+    void install(class UpdateSource& source, const char* via);
+    void notify(const std::string& text, NotificationLevel level);
+
+    KeyValueStore& store_;
+    WifiService& wifi_;
+    SavedNetworks& saved_;
+    StorageService& storage_;
+    EventBus& bus_;
+    const Settings& settings_;
+    TaskHandle_t task_ = nullptr;
+    volatile Phase phase_ = Phase::Idle;
+    volatile int percent_ = 0;
+    std::string incoming_;
+    bool probation_ = false;
+    volatile bool firstFrame_ = false;
+};
+
+}  // namespace roro

src/services/wifi_service.cpp

@@ -7,6 +7,10 @@
 namespace roro {
 
 
+std::string WifiService::ip() const {
+    return controller_.state() == WifiController::State::Connected ? WiFi.localIP().toString().c_str() : "";
+}
+
 int WifiService::rssi() const {
     return controller_.state() == WifiController::State::Connected ? WiFi.RSSI() : 0;
 }

src/services/wifi_service.h

@@ -25,6 +25,7 @@ class WifiService : public Service {
     WifiController::State state() const { return controller_.state(); }
     const std::string& ssid() const { return controller_.ssid(); }
     int rssi() const;
+    std::string ip() const;  // empty unless Connected
 
     // Scans for a list of nearby networks (all channels, or just one for a quick refresh); results
     // arrive in listScan() when listScanDone(), and listScanSeq() counts completed scans.

src/ui/screen.cpp

@@ -2,6 +2,8 @@
 
 #include <M5Cardputer.h>
 
+#include "fonts.h"
+
 namespace roro {
 
 bool Screen::begin() {
@@ -21,4 +23,23 @@ void Screen::render(AppManager& apps, const StatusInfo& status, const Toast* toa
     canvas_.pushSprite(&M5Cardputer.Display, 0, 0);
 }
 
+void Screen::renderUpdate(const std::string& title, const std::string& detail, int percent) {
+    canvas_.fillSprite(theme::kBackground);
+    canvas_.setTextDatum(top_center);
+    canvas_.setFont(&fonts::bold);
+    canvas_.setTextColor(theme::kAccent);
+    canvas_.drawString(title.c_str(), theme::kWidth / 2, 34);
+    canvas_.setFont(&fonts::body);
+    canvas_.setTextColor(theme::kText);
+    canvas_.drawString(detail.c_str(), theme::kWidth / 2, 56);
+    if (percent >= 0) {
+        const int x = 20, y = 82, w = theme::kWidth - 40, h = 12;
+        canvas_.drawRect(x, y, w, h, theme::kMuted);
+        canvas_.fillRect(x + 1, y + 1, (w - 2) * percent / 100, h - 2, theme::kAccent);
+        canvas_.drawString((std::to_string(percent) + "%").c_str(), theme::kWidth / 2, y + 18);
+    }
+    canvas_.setTextDatum(top_left);
+    canvas_.pushSprite(&M5Cardputer.Display, 0, 0);
+}
+
 }  // namespace roro

src/ui/screen.h

@@ -11,6 +11,8 @@ class Screen {
    public:
     bool begin();  // allocates the frame buffer (~32 KB at 8-bit colour)
     void render(AppManager& apps, const StatusInfo& status, const Toast* toast);
+    // Takes over the screen while a Firmware Update is received or about to restart.
+    void renderUpdate(const std::string& title, const std::string& detail, int percent);
     Canvas& canvas() { return canvas_; }
 
    private:

src/ui/widgets.cpp

@@ -48,6 +48,13 @@ void statusBar(Canvas& c, const StatusInfo& info) {
         case StatusInfo::Wifi::Monitoring: right("MON", kAccent); break;
         case StatusInfo::Wifi::None: break;
     }
+    if (info.tracking) right("REC", kWarning);
+    switch (info.gnss) {  // Q61: muted while searching, normal with a Fix, the count with a 3D Fix
+        case StatusInfo::Gnss::Searching: right("G", kMuted); break;
+        case StatusInfo::Gnss::TwoD: right("G", kText); break;
+        case StatusInfo::Gnss::ThreeD: right("G" + std::to_string(info.gnssSatellites), kText); break;
+        case StatusInfo::Gnss::None: break;
+    }
     if (info.compose) right(std::string("opt ") + (info.compose == '*' ? "" : std::string(1, info.compose)), kAccent);
     c.setTextDatum(top_left);
 }

src/ui/widgets.h

@@ -24,11 +24,15 @@ struct StatusInfo {
     enum class Wifi { None, Searching, Connected, Monitoring } wifi = Wifi::None;
     int wifiBars = 0;  // 0..3 when Connected
     int unread = 0;    // unread messages across Services
+    enum class Gnss { None, Searching, TwoD, ThreeD } gnss = Gnss::None;  // None: GNSS off (Q61)
+    int gnssSatellites = 0;  // used in the Fix
+    bool tracking = false;   // a Track is recording (Q63)
 
     bool operator==(const StatusInfo& o) const {
         return title == o.title && batteryPercent == o.batteryPercent && clock == o.clock &&
                sdPresent == o.sdPresent && sdLevel == o.sdLevel && compose == o.compose && wifi == o.wifi &&
-               wifiBars == o.wifiBars && unread == o.unread;
+               wifiBars == o.wifiBars && unread == o.unread && gnss == o.gnss && gnssSatellites == o.gnssSatellites &&
+               tracking == o.tracking;
     }
     bool operator!=(const StatusInfo& o) const { return !(*this == o); }
 };

test/test_file_receiver/test_file_receiver.cpp

@@ -0,0 +1,202 @@
+#include <unity.h>
+
+#include <string>
+#include <vector>
+
+#include "file_receiver.h"
+#include "sha256.h"
+
+using namespace roro;
+
+void setUp() {}
+void tearDown() {}
+
+static std::string hexSha(const std::vector<uint8_t>& data) {
+    uint8_t d[32];
+    Sha256::hash(data.data(), data.size(), d);
+    static const char* hex = "0123456789abcdef";
+    std::string s;
+    for (uint8_t b : d) {
+        s += hex[b >> 4];
+        s += hex[b & 15];
+    }
+    return s;
+}
+
+static std::vector<uint8_t> bytes(size_t n) {
+    std::vector<uint8_t> v(n);
+    for (size_t i = 0; i < n; i++) v[i] = static_cast<uint8_t>(i * 7 + 3);
+    return v;
+}
+
+static std::string args(const std::string& path, const std::vector<uint8_t>& data) {
+    return path + " " + std::to_string(data.size()) + " " + hexSha(data);
+}
+
+void test_begin_accepts_path_size_and_checksum() {
+    FileReceiver r;
+    auto data = bytes(10);
+    TEST_ASSERT_EQUAL_STRING("", r.begin(args("/updates/a.ota", data), 0).c_str());
+    TEST_ASSERT_TRUE(r.state() == FileReceiver::State::Receiving);
+    TEST_ASSERT_EQUAL_STRING("/updates/a.ota", r.path().c_str());
+    TEST_ASSERT_EQUAL_STRING("/updates/a.ota.part", r.partPath().c_str());
+    TEST_ASSERT_EQUAL_UINT32(10, r.size());
+}
+
+void test_begin_refuses_bad_arguments() {
+    FileReceiver r;
+    std::string sha(64, 'a');
+    TEST_ASSERT_NOT_EQUAL(0, r.begin("updates/a.ota 10 " + sha, 0).size());   // not absolute
+    TEST_ASSERT_NOT_EQUAL(0, r.begin("/a/../b.ota 10 " + sha, 0).size());     // climbs out
+    TEST_ASSERT_NOT_EQUAL(0, r.begin("/a.ota 0 " + sha, 0).size());           // empty
+    TEST_ASSERT_NOT_EQUAL(0, r.begin("/a.ota 99999999 " + sha, 0).size());    // too big
+    TEST_ASSERT_NOT_EQUAL(0, r.begin("/a.ota 1x " + sha, 0).size());          // not a number
+    TEST_ASSERT_NOT_EQUAL(0, r.begin("/a.ota 10 abc", 0).size());             // short checksum
+    TEST_ASSERT_NOT_EQUAL(0, r.begin("/a.ota 10 " + std::string(64, 'g'), 0).size());
+    TEST_ASSERT_NOT_EQUAL(0, r.begin("/a.ota 10", 0).size());
+    TEST_ASSERT_TRUE(r.state() == FileReceiver::State::Idle);
+}
+
+void test_bytes_are_handed_out_one_chunk_at_a_time() {
+    FileReceiver r;
+    auto data = bytes(FileReceiver::kChunk * 2 + 100);
+    r.begin(args("/f.bin", data), 0);
+
+    // Everything arrives at once: only the first chunk is taken.
+    TEST_ASSERT_EQUAL(FileReceiver::kChunk, r.feed(data.data(), data.size(), 1));
+    TEST_ASSERT_TRUE(r.state() == FileReceiver::State::Writing);
+    TEST_ASSERT_EQUAL(FileReceiver::kChunk, r.chunk().size());
+    TEST_ASSERT_EQUAL(0, r.feed(data.data() + FileReceiver::kChunk, 10, 2));  // nothing more while writing
+
+    r.chunkWritten(true, 3);
+    TEST_ASSERT_TRUE(r.state() == FileReceiver::State::Receiving);
+    TEST_ASSERT_EQUAL_UINT32(FileReceiver::kChunk, r.received());
+
+    r.feed(data.data() + FileReceiver::kChunk, FileReceiver::kChunk, 4);
+    r.chunkWritten(true, 5);
+    // The last, short chunk is complete as soon as the announced size is reached.
+    TEST_ASSERT_EQUAL(100, r.feed(data.data() + 2 * FileReceiver::kChunk, 100, 6));
+    TEST_ASSERT_TRUE(r.state() == FileReceiver::State::Writing);
+    TEST_ASSERT_EQUAL(100, r.chunk().size());
+    TEST_ASSERT_EQUAL_UINT8(data[2 * FileReceiver::kChunk], r.chunk()[0]);
+
+    r.chunkWritten(true, 7);
+    TEST_ASSERT_TRUE(r.state() == FileReceiver::State::Finishing);
+    r.finished(true);
+    TEST_ASSERT_TRUE(r.state() == FileReceiver::State::Done);
+}
+
+void test_chunk_split_across_reads() {
+    FileReceiver r;
+    auto data = bytes(30);
+    r.begin(args("/f.bin", data), 0);
+    TEST_ASSERT_EQUAL(10, r.feed(data.data(), 10, 1));
+    TEST_ASSERT_TRUE(r.state() == FileReceiver::State::Receiving);
+    TEST_ASSERT_EQUAL(20, r.feed(data.data() + 10, 20, 2));
+    TEST_ASSERT_TRUE(r.state() == FileReceiver::State::Writing);
+    TEST_ASSERT_EQUAL(30, r.chunk().size());
+}
+
+void test_wrong_checksum_fails_before_the_last_write() {
+    FileReceiver r;
+    auto data = bytes(50);
+    r.begin(args("/f.bin", data), 0);
+    data[20] ^= 1;  // corrupted on the way
+    r.feed(data.data(), data.size(), 1);
+    TEST_ASSERT_TRUE(r.state() == FileReceiver::State::Failed);
+    TEST_ASSERT_EQUAL_STRING("checksum mismatch", r.error().c_str());
+}
+
+void test_failed_write_fails_the_transfer() {
+    FileReceiver r;
+    auto data = bytes(50);
+    r.begin(args("/f.bin", data), 0);
+    r.feed(data.data(), data.size(), 1);
+    r.chunkWritten(false, 2);
+    TEST_ASSERT_TRUE(r.state() == FileReceiver::State::Failed);
+    TEST_ASSERT_EQUAL_STRING("write failed", r.error().c_str());
+}
+
+void test_failed_rename_fails_the_transfer() {
+    FileReceiver r;
+    auto data = bytes(5);
+    r.begin(args("/f.bin", data), 0);
+    r.feed(data.data(), data.size(), 1);
+    r.chunkWritten(true, 2);
+    r.finished(false);
+    TEST_ASSERT_TRUE(r.state() == FileReceiver::State::Failed);
+}
+
+void test_silence_times_out() {
+    FileReceiver r;
+    auto data = bytes(FileReceiver::kChunk * 2);
+    r.begin(args("/f.bin", data), 1000);
+    r.tick(1000 + FileReceiver::kTimeoutMs - 1);
+    TEST_ASSERT_TRUE(r.state() == FileReceiver::State::Receiving);
+    r.feed(data.data(), 10, 5000);  // bytes reset the clock
+    r.tick(5000 + FileReceiver::kTimeoutMs - 1);
+    TEST_ASSERT_TRUE(r.state() == FileReceiver::State::Receiving);
+    r.tick(5000 + FileReceiver::kTimeoutMs);
+    TEST_ASSERT_TRUE(r.state() == FileReceiver::State::Failed);
+    TEST_ASSERT_EQUAL_STRING("timed out", r.error().c_str());
+}
+
+void test_a_write_that_never_completes_times_out() {
+    // With no card mounted, the storage task drops the job and never answers.
+    FileReceiver r;
+    auto data = bytes(10);
+    r.begin(args("/f.bin", data), 0);
+    r.feed(data.data(), data.size(), 100);
+    r.tick(100 + FileReceiver::kTimeoutMs);
+    TEST_ASSERT_TRUE(r.state() == FileReceiver::State::Failed);
+}
+
+void test_wanted_counts_down_within_a_chunk() {
+    FileReceiver r;
+    auto data = bytes(FileReceiver::kChunk + 10);
+    TEST_ASSERT_EQUAL(0, r.wanted());
+    r.begin(args("/f.bin", data), 0);
+    TEST_ASSERT_EQUAL(FileReceiver::kChunk, r.wanted());
+    r.feed(data.data(), 24, 1);
+    TEST_ASSERT_EQUAL(FileReceiver::kChunk - 24, r.wanted());
+    r.feed(data.data() + 24, FileReceiver::kChunk - 24, 2);
+    TEST_ASSERT_EQUAL(0, r.wanted());  // writing
+    r.chunkWritten(true, 3);
+    TEST_ASSERT_EQUAL(10, r.wanted());  // the short last chunk
+}
+
+void test_a_rename_that_never_completes_times_out() {
+    FileReceiver r;
+    auto data = bytes(10);
+    r.begin(args("/f.bin", data), 0);
+    r.feed(data.data(), data.size(), 1);
+    r.chunkWritten(true, 2);
+    r.tick(2 + FileReceiver::kTimeoutMs);
+    TEST_ASSERT_TRUE(r.state() == FileReceiver::State::Failed);
+}
+
+void test_reset_returns_to_idle() {
+    FileReceiver r;
+    auto data = bytes(10);
+    r.begin(args("/f.bin", data), 0);
+    r.reset();
+    TEST_ASSERT_TRUE(r.state() == FileReceiver::State::Idle);
+    TEST_ASSERT_FALSE(r.active());
+}
+
+int main() {
+    UNITY_BEGIN();
+    RUN_TEST(test_begin_accepts_path_size_and_checksum);
+    RUN_TEST(test_begin_refuses_bad_arguments);
+    RUN_TEST(test_bytes_are_handed_out_one_chunk_at_a_time);
+    RUN_TEST(test_chunk_split_across_reads);
+    RUN_TEST(test_wrong_checksum_fails_before_the_last_write);
+    RUN_TEST(test_failed_write_fails_the_transfer);
+    RUN_TEST(test_failed_rename_fails_the_transfer);
+    RUN_TEST(test_silence_times_out);
+    RUN_TEST(test_a_write_that_never_completes_times_out);
+    RUN_TEST(test_wanted_counts_down_within_a_chunk);
+    RUN_TEST(test_a_rename_that_never_completes_times_out);
+    RUN_TEST(test_reset_returns_to_idle);
+    return UNITY_END();
+}

test/test_gemini/test_gemini.cpp

@@ -0,0 +1,223 @@
+#include <unity.h>
+
+#include <string>
+
+#include "gemini_response.h"
+#include "gemini_url.h"
+#include "gemtext.h"
+#include "text_buffer.h"
+
+using namespace roro::gemini;
+
+void setUp() {}
+void tearDown() {}
+
+static void resolvesTo(const char* ref, const char* expected) {
+    TEST_ASSERT_EQUAL_STRING_MESSAGE(expected, resolve("gemini://a/b/c/d;p?q", ref).c_str(), ref);
+}
+
+// RFC 3986, section 5.4.1, with gemini:// for http://.
+void test_rfc3986_normal_examples() {
+    resolvesTo("g:h", "g:h");
+    resolvesTo("g", "gemini://a/b/c/g");
+    resolvesTo("./g", "gemini://a/b/c/g");
+    resolvesTo("g/", "gemini://a/b/c/g/");
+    resolvesTo("/g", "gemini://a/g");
+    resolvesTo("//g", "gemini://g");
+    resolvesTo("?y", "gemini://a/b/c/d;p?y");
+    resolvesTo("g?y", "gemini://a/b/c/g?y");
+    resolvesTo("#s", "gemini://a/b/c/d;p?q#s");
+    resolvesTo("g#s", "gemini://a/b/c/g#s");
+    resolvesTo("g?y#s", "gemini://a/b/c/g?y#s");
+    resolvesTo(";x", "gemini://a/b/c/;x");
+    resolvesTo("", "gemini://a/b/c/d;p?q");
+    resolvesTo(".", "gemini://a/b/c/");
+    resolvesTo("./", "gemini://a/b/c/");
+    resolvesTo("..", "gemini://a/b/");
+    resolvesTo("../", "gemini://a/b/");
+    resolvesTo("../g", "gemini://a/b/g");
+    resolvesTo("../..", "gemini://a/");
+    resolvesTo("../../", "gemini://a/");
+    resolvesTo("../../g", "gemini://a/g");
+}
+
+// Section 5.4.2.
+void test_rfc3986_abnormal_examples() {
+    resolvesTo("../../../g", "gemini://a/g");
+    resolvesTo("../../../../g", "gemini://a/g");
+    resolvesTo("/./g", "gemini://a/g");
+    resolvesTo("/../g", "gemini://a/g");
+    resolvesTo("g.", "gemini://a/b/c/g.");
+    resolvesTo(".g", "gemini://a/b/c/.g");
+    resolvesTo("./../g", "gemini://a/b/g");
+    resolvesTo("g/./h", "gemini://a/b/c/g/h");
+    resolvesTo("g/../h", "gemini://a/b/c/h");
+    resolvesTo("g;x=1/./y", "gemini://a/b/c/g;x=1/y");
+    resolvesTo("g;x=1/../y", "gemini://a/b/c/y");
+}
+
+void test_parse_a_gemini_url() {
+    Url u;
+    TEST_ASSERT_TRUE(parseUrl("gemini://Example.ORG:1966/a/b?c=d#e", u));
+    TEST_ASSERT_EQUAL_STRING("gemini", u.scheme.c_str());
+    TEST_ASSERT_EQUAL_STRING("example.org", u.host.c_str());  // hosts are case-insensitive
+    TEST_ASSERT_EQUAL(1966, u.port);
+    TEST_ASSERT_EQUAL_STRING("/a/b", u.path.c_str());
+    TEST_ASSERT_EQUAL_STRING("c=d", u.query.c_str());
+    TEST_ASSERT_EQUAL_STRING("e", u.fragment.c_str());
+    TEST_ASSERT_TRUE(parseUrl("gemini://example.org", u));
+    TEST_ASSERT_EQUAL(1965, u.portOrDefault());
+    TEST_ASSERT_FALSE(parseUrl("not a url", u));
+}
+
+void test_the_request_drops_the_fragment_and_never_has_an_empty_path() {
+    TEST_ASSERT_EQUAL_STRING("gemini://example.org/", requestUrl("gemini://example.org").c_str());
+    TEST_ASSERT_EQUAL_STRING("gemini://example.org/a?b", requestUrl("gemini://example.org/a?b#frag").c_str());
+    TEST_ASSERT_EQUAL_STRING("gemini://example.org:1966/", requestUrl("gemini://EXAMPLE.org:1966").c_str());
+}
+
+void test_other_schemes_are_recognised() {
+    TEST_ASSERT_TRUE(isGemini("gemini://a/"));
+    TEST_ASSERT_FALSE(isGemini("https://a/"));
+    TEST_ASSERT_FALSE(isGemini("gopher://a/"));
+    TEST_ASSERT_FALSE(isGemini("mailto:someone@example.org"));
+}
+
+void test_query_encoding() {
+    TEST_ASSERT_EQUAL_STRING("hello%20world", encodeQuery("hello world").c_str());
+    TEST_ASSERT_EQUAL_STRING("caf%C3%A9%3F%26", encodeQuery("caf\xC3\xA9?&").c_str());
+    TEST_ASSERT_EQUAL_STRING("a-b_c.d~e", encodeQuery("a-b_c.d~e").c_str());
+}
+
+void test_response_header() {
+    Header h;
+    TEST_ASSERT_TRUE(parseHeader("20 text/gemini; charset=utf-8; lang=en", h));
+    TEST_ASSERT_EQUAL(20, h.status);
+    TEST_ASSERT_EQUAL_STRING("text/gemini", h.mimeType().c_str());
+    TEST_ASSERT_EQUAL_STRING("utf-8", h.parameter("charset").c_str());
+    TEST_ASSERT_TRUE(h.category() == Category::Success);
+    TEST_ASSERT_TRUE(parseHeader("20", h));  // no MIME type: text/gemini by default
+    TEST_ASSERT_EQUAL_STRING("text/gemini", h.mimeType().c_str());
+    TEST_ASSERT_TRUE(parseHeader("31 gemini://cosmos.skyjake.fi/", h));
+    TEST_ASSERT_TRUE(h.category() == Category::Redirect);
+    TEST_ASSERT_EQUAL_STRING("gemini://cosmos.skyjake.fi/", h.meta.c_str());
+    TEST_ASSERT_TRUE(parseHeader("11 Password", h));
+    TEST_ASSERT_TRUE(h.category() == Category::Input);
+    TEST_ASSERT_TRUE(h.sensitiveInput());
+    TEST_ASSERT_TRUE(parseHeader("51 Not found", h));
+    TEST_ASSERT_TRUE(h.category() == Category::PermanentFailure);
+    TEST_ASSERT_TRUE(parseHeader("60 Certificate required", h));
+    TEST_ASSERT_TRUE(h.category() == Category::ClientCertificate);
+}
+
+void test_malformed_headers_are_refused() {
+    Header h;
+    TEST_ASSERT_FALSE(parseHeader("", h));
+    TEST_ASSERT_FALSE(parseHeader("2 text/gemini", h));
+    TEST_ASSERT_FALSE(parseHeader("ab text/gemini", h));
+    TEST_ASSERT_FALSE(parseHeader("20text/gemini", h));
+    TEST_ASSERT_FALSE(parseHeader("20 " + std::string(1025, 'x'), h));
+}
+
+void test_gemtext_line_types() {
+    auto lines = parseGemtext(
+        "# Title\n## Sub\n### Subsub\nPlain text\n* item\n> quoted\n=> gemini://a/b Label here\n=>/rel\n"
+        "```ascii art\n# not a heading\n=> not a link\n```\nafter\n");
+    TEST_ASSERT_EQUAL(13, static_cast<int>(lines.size()));
+    TEST_ASSERT_TRUE(lines[0].type == LineType::Heading1);
+    TEST_ASSERT_EQUAL_STRING("Title", lines[0].text.c_str());
+    TEST_ASSERT_TRUE(lines[1].type == LineType::Heading2);
+    TEST_ASSERT_TRUE(lines[2].type == LineType::Heading3);
+    TEST_ASSERT_TRUE(lines[3].type == LineType::Text);
+    TEST_ASSERT_TRUE(lines[4].type == LineType::ListItem);
+    TEST_ASSERT_EQUAL_STRING("item", lines[4].text.c_str());
+    TEST_ASSERT_TRUE(lines[5].type == LineType::Quote);
+    TEST_ASSERT_EQUAL_STRING("quoted", lines[5].text.c_str());
+    TEST_ASSERT_TRUE(lines[6].type == LineType::Link);
+    TEST_ASSERT_EQUAL_STRING("gemini://a/b", lines[6].url.c_str());
+    TEST_ASSERT_EQUAL_STRING("Label here", lines[6].text.c_str());
+    TEST_ASSERT_TRUE(lines[7].type == LineType::Link);
+    TEST_ASSERT_EQUAL_STRING("/rel", lines[7].url.c_str());
+    TEST_ASSERT_EQUAL_STRING("/rel", lines[7].text.c_str());  // no label: the URL is the label
+    TEST_ASSERT_TRUE(lines[8].type == LineType::PreToggle);
+    TEST_ASSERT_EQUAL_STRING("ascii art", lines[8].text.c_str());
+    TEST_ASSERT_TRUE(lines[9].type == LineType::Preformatted);
+    TEST_ASSERT_EQUAL_STRING("# not a heading", lines[9].text.c_str());
+    TEST_ASSERT_TRUE(lines[10].type == LineType::Preformatted);
+    TEST_ASSERT_TRUE(lines[11].type == LineType::PreToggle);
+    TEST_ASSERT_TRUE(lines[12].type == LineType::Text);
+}
+
+void test_gemtext_handles_crlf_and_a_missing_last_newline() {
+    auto lines = parseGemtext("one\r\n=>\tgemini://x/\t  spaced label \r\ntwo");
+    TEST_ASSERT_EQUAL(3, static_cast<int>(lines.size()));
+    TEST_ASSERT_EQUAL_STRING("one", lines[0].text.c_str());
+    TEST_ASSERT_EQUAL_STRING("gemini://x/", lines[1].url.c_str());
+    TEST_ASSERT_EQUAL_STRING("spaced label", lines[1].text.c_str());
+    TEST_ASSERT_EQUAL_STRING("two", lines[2].text.c_str());
+}
+
+void test_display_text_keeps_latin1_and_replaces_the_rest() {
+    TEST_ASSERT_EQUAL_STRING("caf\xC3\xA9", displayText("caf\xC3\xA9").c_str());   // é stays
+    TEST_ASSERT_EQUAL_STRING("? and ?", displayText("\xE2\x9C\x93 and \xF0\x9F\x99\x82").c_str());  // ✓ and 🙂
+    TEST_ASSERT_EQUAL_STRING("bad ? byte", displayText("bad \xFF byte").c_str());
+    TEST_ASSERT_EQUAL_STRING("a   b", displayText("a\tb").c_str());  // tab: three spaces here
+}
+
+void test_saved_page_paths() {
+    TEST_ASSERT_EQUAL_STRING("/gemini/saved/example.org/index.gmi", savedPath("gemini://example.org/").c_str());
+    TEST_ASSERT_EQUAL_STRING("/gemini/saved/example.org/index.gmi", savedPath("gemini://example.org").c_str());
+    TEST_ASSERT_EQUAL_STRING("/gemini/saved/example.org/log/2026/post.gmi",
+                             savedPath("gemini://example.org/log/2026/post.gmi").c_str());
+    TEST_ASSERT_EQUAL_STRING("/gemini/saved/example.org/log/index.gmi", savedPath("gemini://example.org/log/").c_str());
+    TEST_ASSERT_EQUAL_STRING("/gemini/saved/example.org/about.gmi", savedPath("gemini://example.org/about").c_str());
+    TEST_ASSERT_EQUAL_STRING("/gemini/saved/example.org_1966/a~q_x.gmi",
+                             savedPath("gemini://example.org:1966/a?q:x#frag").c_str());
+}
+
+void test_text_buffer_keeps_lines_across_any_feed() {
+    TextBuffer b;
+    std::string doc = "# Title\r\nline two\n\nlast without end";
+    for (size_t i = 0; i < doc.size(); i += 3) b.append(doc.data() + i, std::min<size_t>(3, doc.size() - i));
+    b.finish();
+    TEST_ASSERT_EQUAL(4, static_cast<int>(b.lineCount()));
+    TEST_ASSERT_EQUAL_STRING("# Title", b.line(0).c_str());
+    TEST_ASSERT_EQUAL_STRING("line two", b.line(1).c_str());
+    TEST_ASSERT_EQUAL_STRING("", b.line(2).c_str());
+    TEST_ASSERT_EQUAL_STRING("last without end", b.line(3).c_str());
+    TEST_ASSERT_EQUAL(doc.size(), b.bytes());
+}
+
+void test_text_buffer_spreads_over_chunks_without_splitting_lines() {
+    TextBuffer b;
+    std::string line(1000, 'x');
+    for (int i = 0; i < 20; i++) {
+        std::string l = std::to_string(i) + line + "\n";
+        b.append(l.data(), l.size());
+    }
+    std::string big(6000, 'y');  // longer than a chunk
+    big += "\n";
+    b.append(big.data(), big.size());
+    TEST_ASSERT_EQUAL(21, static_cast<int>(b.lineCount()));
+    for (int i = 0; i < 20; i++) TEST_ASSERT_EQUAL_STRING((std::to_string(i) + line).c_str(), b.line(i).c_str());
+    TEST_ASSERT_EQUAL(6000, static_cast<int>(b.line(20).size()));
+}
+
+int main() {
+    UNITY_BEGIN();
+    RUN_TEST(test_rfc3986_normal_examples);
+    RUN_TEST(test_rfc3986_abnormal_examples);
+    RUN_TEST(test_parse_a_gemini_url);
+    RUN_TEST(test_the_request_drops_the_fragment_and_never_has_an_empty_path);
+    RUN_TEST(test_other_schemes_are_recognised);
+    RUN_TEST(test_query_encoding);
+    RUN_TEST(test_response_header);
+    RUN_TEST(test_malformed_headers_are_refused);
+    RUN_TEST(test_gemtext_line_types);
+    RUN_TEST(test_gemtext_handles_crlf_and_a_missing_last_newline);
+    RUN_TEST(test_display_text_keeps_latin1_and_replaces_the_rest);
+    RUN_TEST(test_saved_page_paths);
+    RUN_TEST(test_text_buffer_keeps_lines_across_any_feed);
+    RUN_TEST(test_text_buffer_spreads_over_chunks_without_splitting_lines);
+    return UNITY_END();
+}

test/test_geo_format/test_geo_format.cpp

@@ -0,0 +1,64 @@
+#include <unity.h>
+
+#include "geo_format.h"
+
+using namespace roro::gnss;
+
+void setUp() {}
+void tearDown() {}
+
+void test_decimal_degrees_with_hemisphere() {
+    TEST_ASSERT_EQUAL_STRING("50.86920° N", formatDecimal(50.8692034, true).c_str());
+    TEST_ASSERT_EQUAL_STRING("33.50000° S", formatDecimal(-33.5, true).c_str());
+    TEST_ASSERT_EQUAL_STRING("4.25350° E", formatDecimal(4.2535, false).c_str());
+    TEST_ASSERT_EQUAL_STRING("151.21000° W", formatDecimal(-151.21, false).c_str());
+}
+
+void test_degrees_minutes_seconds() {
+    TEST_ASSERT_EQUAL_STRING("50° 52' 09.1\" N", formatDms(50.8692034, true).c_str());
+    TEST_ASSERT_EQUAL_STRING("4° 15' 12.6\" E", formatDms(4.2535, false).c_str());
+    TEST_ASSERT_EQUAL_STRING("33° 30' 00.0\" S", formatDms(-33.5, true).c_str());
+}
+
+void test_seconds_that_round_up_carry_over() {
+    TEST_ASSERT_EQUAL_STRING("11° 00' 00.0\" N", formatDms(10.9999999, true).c_str());
+}
+
+void test_maidenhead_matches_known_locators() {
+    TEST_ASSERT_EQUAL_STRING("FN31pr", maidenhead(41.714775, -72.727260).c_str());  // W1AW
+    TEST_ASSERT_EQUAL_STRING("JN58td", maidenhead(48.14666, 11.60833).c_str());     // Munich
+    TEST_ASSERT_EQUAL_STRING("JJ00aa", maidenhead(0, 0).c_str());
+    TEST_ASSERT_EQUAL_STRING("AA00aa", maidenhead(-90, -180).c_str());
+}
+
+void test_maidenhead_stays_in_range_at_the_edges() {
+    TEST_ASSERT_EQUAL_STRING("RR99xx", maidenhead(90, 180).c_str());
+}
+
+void test_sky_projection() {
+    SkyPoint zenith = skyPosition(123, 90, 50, 60, 40);
+    TEST_ASSERT_EQUAL(50, zenith.x);
+    TEST_ASSERT_EQUAL(60, zenith.y);
+    SkyPoint north = skyPosition(0, 0, 50, 60, 40);
+    TEST_ASSERT_EQUAL(50, north.x);
+    TEST_ASSERT_EQUAL(20, north.y);  // up
+    SkyPoint east = skyPosition(90, 0, 50, 60, 40);
+    TEST_ASSERT_EQUAL(90, east.x);
+    TEST_ASSERT_EQUAL(60, east.y);
+    SkyPoint south45 = skyPosition(180, 45, 50, 60, 40);
+    TEST_ASSERT_EQUAL(50, south45.x);
+    TEST_ASSERT_EQUAL(80, south45.y);
+    SkyPoint below = skyPosition(270, -5, 50, 60, 40);  // just below the horizon: on the edge
+    TEST_ASSERT_EQUAL(10, below.x);
+}
+
+int main() {
+    UNITY_BEGIN();
+    RUN_TEST(test_decimal_degrees_with_hemisphere);
+    RUN_TEST(test_degrees_minutes_seconds);
+    RUN_TEST(test_seconds_that_round_up_carry_over);
+    RUN_TEST(test_maidenhead_matches_known_locators);
+    RUN_TEST(test_maidenhead_stays_in_range_at_the_edges);
+    RUN_TEST(test_sky_projection);
+    return UNITY_END();
+}

test/test_nmea/test_nmea.cpp

@@ -0,0 +1,236 @@
+#include <unity.h>
+
+#include <cstdio>
+#include <string>
+#include <vector>
+
+#include "nmea_parser.h"
+
+using namespace roro;
+using namespace roro::gnss;
+
+void setUp() {}
+void tearDown() {}
+
+// "$<body>*<checksum>": the checksum is computed here, so scenarios stay readable.
+static std::string nmea(const std::string& body) {
+    uint8_t sum = 0;
+    for (char c : body) sum ^= static_cast<uint8_t>(c);
+    char tail[4];
+    std::snprintf(tail, sizeof tail, "*%02X", sum);
+    return "$" + body + tail;
+}
+
+static void feedLine(NmeaParser& p, const std::string& line) {
+    std::string withEnd = line + "\r\n";
+    p.feed(withEnd.data(), withEnd.size());
+}
+
+void test_checksum_is_verified() {
+    NmeaParser p;
+    TEST_ASSERT_TRUE(p.sentence("$GNVTG,,,,,,,,,N*2E"));  // captured from the device
+    TEST_ASSERT_FALSE(p.sentence("$GNVTG,,,,,,,,,N*2F"));
+    TEST_ASSERT_FALSE(p.sentence("$GNVTG,,,,,,,,,N"));
+    TEST_ASSERT_FALSE(p.sentence("GNVTG,,,,,,,,,N*2E"));
+    TEST_ASSERT_EQUAL_UINT32(3, p.badSentences());
+    TEST_ASSERT_EQUAL_UINT32(1, p.goodSentences());
+}
+
+void test_no_fix_as_captured_indoors() {
+    NmeaParser p;
+    feedLine(p, "$GNRMC,200231.00,V,,,,,,,041026,,,N,V*1A");
+    feedLine(p, "$GNGGA,200231.00,,,,,0,00,25.5,,,,,,*48");
+    feedLine(p, "$GNGSA,A,1,,,,,,,,,,,,,25.5,25.5,25.5,1*01");
+    feedLine(p, "$GPGSV,1,1,01,25,41,108,17,1*58");
+    feedLine(p, "$GLGSV,1,1,00,1*78");
+    const GnssState& s = p.state();
+    TEST_ASSERT_TRUE(s.fix == FixType::None);
+    TEST_ASSERT_FALSE(s.positionValid);
+    TEST_ASSERT_FALSE(s.timeValid);  // a time without a Fix isn't trusted
+    TEST_ASSERT_EQUAL(1, static_cast<int>(s.satellites.size()));
+    TEST_ASSERT_TRUE(s.satellites[0].system == Constellation::Gps);
+    TEST_ASSERT_EQUAL(25, s.satellites[0].prn);
+    TEST_ASSERT_EQUAL(41, s.satellites[0].elevation);
+    TEST_ASSERT_EQUAL(108, s.satellites[0].azimuth);
+    TEST_ASSERT_EQUAL(17, s.satellites[0].snr);
+    TEST_ASSERT_FALSE(s.satellites[0].used);
+}
+
+void test_rmc_with_a_fix_gives_position_time_speed_course() {
+    NmeaParser p;
+    feedLine(p, nmea("GNRMC,123519.00,A,5050.8136,N,00421.1532,E,10.0,84.4,041026,,,A,V"));
+    const GnssState& s = p.state();
+    TEST_ASSERT_TRUE(s.positionValid);
+    TEST_ASSERT_FLOAT_WITHIN(1e-6, 50.0 + 50.8136 / 60.0, s.latitude);
+    TEST_ASSERT_FLOAT_WITHIN(1e-6, 4.0 + 21.1532 / 60.0, s.longitude);
+    TEST_ASSERT_TRUE(s.timeValid);
+    TEST_ASSERT_EQUAL(2026, s.year);
+    TEST_ASSERT_EQUAL(10, s.month);
+    TEST_ASSERT_EQUAL(4, s.day);
+    TEST_ASSERT_EQUAL(12, s.hour);
+    TEST_ASSERT_EQUAL(35, s.minute);
+    TEST_ASSERT_EQUAL(19, s.second);
+    TEST_ASSERT_FLOAT_WITHIN(0.01, 18.52, s.speedKmh);  // 10 knots
+    TEST_ASSERT_TRUE(s.courseValid);
+    TEST_ASSERT_FLOAT_WITHIN(0.01, 84.4, s.courseDeg);
+}
+
+void test_southern_and_western_hemispheres_are_negative() {
+    NmeaParser p;
+    feedLine(p, nmea("GNRMC,000000.00,A,3352.0000,S,15112.6000,W,0.0,,010126,,,A,V"));
+    TEST_ASSERT_FLOAT_WITHIN(1e-6, -(33.0 + 52.0 / 60.0), p.state().latitude);
+    TEST_ASSERT_FLOAT_WITHIN(1e-6, -(151.0 + 12.6 / 60.0), p.state().longitude);
+    TEST_ASSERT_FALSE(p.state().courseValid);  // empty course field
+}
+
+void test_utc_seconds_from_the_fix_time() {
+    NmeaParser p;
+    feedLine(p, nmea("GNRMC,123519.00,A,5050.8136,N,00421.1532,E,0.0,,041026,,,A,V"));
+    TEST_ASSERT_EQUAL_INT64(1791117319LL, p.state().utcSeconds());  // 2026-10-04 12:35:19 UTC
+}
+
+void test_gga_gives_fix_quality_altitude_satellites_and_hdop() {
+    NmeaParser p;
+    feedLine(p, nmea("GNGGA,123519.00,5050.8136,N,00421.1532,E,1,09,0.9,61.4,M,46.9,M,,"));
+    feedLine(p, nmea("GNGSA,A,3,05,13,15,18,23,,,,,,,,1.6,0.9,1.3,1"));
+    const GnssState& s = p.state();
+    TEST_ASSERT_TRUE(s.positionValid);
+    TEST_ASSERT_EQUAL(9, s.satellitesUsed);
+    TEST_ASSERT_FLOAT_WITHIN(0.01, 0.9, s.hdop);
+    TEST_ASSERT_TRUE(s.altitudeValid);
+    TEST_ASSERT_FLOAT_WITHIN(0.01, 61.4, s.altitudeM);
+    TEST_ASSERT_TRUE(s.fix == FixType::ThreeD);
+}
+
+void test_fix_type_comes_from_gsa_mode() {
+    NmeaParser p;
+    feedLine(p, nmea("GNGSA,A,2,05,13,15,,,,,,,,,,2.1,1.9,1.0,1"));
+    TEST_ASSERT_TRUE(p.state().fix == FixType::TwoD);
+    feedLine(p, nmea("GNGSA,A,1,,,,,,,,,,,,,25.5,25.5,25.5,1"));
+    TEST_ASSERT_TRUE(p.state().fix == FixType::None);
+}
+
+void test_losing_the_fix_drops_the_position() {
+    NmeaParser p;
+    feedLine(p, nmea("GNRMC,123519.00,A,5050.8136,N,00421.1532,E,0.0,,041026,,,A,V"));
+    TEST_ASSERT_TRUE(p.state().positionValid);
+    feedLine(p, nmea("GNRMC,123520.00,V,,,,,,,041026,,,N,V"));
+    TEST_ASSERT_FALSE(p.state().positionValid);
+    TEST_ASSERT_FALSE(p.state().timeValid);
+}
+
+void test_gsv_sequence_spans_several_messages() {
+    NmeaParser p;
+    feedLine(p, nmea("GPGSV,2,1,05,05,60,120,40,13,45,200,35,15,30,300,30,18,20,050,25,1"));
+    TEST_ASSERT_EQUAL(0, static_cast<int>(p.state().satellites.size()));  // committed at the last message
+    feedLine(p, nmea("GPGSV,2,2,05,23,10,010,,1"));
+    const auto& sats = p.state().satellites;
+    TEST_ASSERT_EQUAL(5, static_cast<int>(sats.size()));
+    TEST_ASSERT_EQUAL(-1, sats[4].snr);  // not tracked: empty SNR
+}
+
+void test_each_constellation_keeps_its_own_satellites() {
+    NmeaParser p;
+    feedLine(p, nmea("GPGSV,1,1,01,05,60,120,40,1"));
+    feedLine(p, nmea("GLGSV,1,1,01,70,30,90,33,1"));
+    feedLine(p, nmea("GAGSV,1,1,01,11,20,45,28,7"));
+    feedLine(p, nmea("GBGSV,1,1,01,24,50,270,36,1"));
+    feedLine(p, nmea("GQGSV,1,1,01,02,70,180,41,1"));
+    const auto& sats = p.state().satellites;
+    TEST_ASSERT_EQUAL(5, static_cast<int>(sats.size()));
+    int seen[8] = {};
+    for (auto& s : sats) seen[static_cast<int>(s.system)]++;
+    TEST_ASSERT_EQUAL(1, seen[static_cast<int>(Constellation::Gps)]);
+    TEST_ASSERT_EQUAL(1, seen[static_cast<int>(Constellation::Glonass)]);
+    TEST_ASSERT_EQUAL(1, seen[static_cast<int>(Constellation::Galileo)]);
+    TEST_ASSERT_EQUAL(1, seen[static_cast<int>(Constellation::BeiDou)]);
+    TEST_ASSERT_EQUAL(1, seen[static_cast<int>(Constellation::Qzss)]);
+}
+
+void test_a_satellite_on_two_bands_counts_once_with_the_stronger_signal() {
+    NmeaParser p;
+    feedLine(p, nmea("GPGSV,1,1,01,05,60,120,30,1"));  // L1
+    feedLine(p, nmea("GPGSV,1,1,01,05,60,120,42,8"));  // L5
+    const auto& sats = p.state().satellites;
+    TEST_ASSERT_EQUAL(1, static_cast<int>(sats.size()));
+    TEST_ASSERT_EQUAL(42, sats[0].snr);
+}
+
+void test_an_empty_gsv_clears_that_constellation() {
+    NmeaParser p;
+    feedLine(p, nmea("GLGSV,1,1,01,70,30,90,33,1"));
+    TEST_ASSERT_EQUAL(1, static_cast<int>(p.state().satellites.size()));
+    feedLine(p, "$GLGSV,1,1,00,1*78");  // captured
+    TEST_ASSERT_EQUAL(0, static_cast<int>(p.state().satellites.size()));
+}
+
+void test_gsa_marks_the_satellites_used_per_system() {
+    NmeaParser p;
+    feedLine(p, nmea("GPGSV,1,1,02,05,60,120,40,13,45,200,35,1"));
+    feedLine(p, nmea("GBGSV,1,1,01,05,50,270,36,1"));  // BeiDou 5, not GPS 5
+    feedLine(p, nmea("GNGSA,A,3,05,,,,,,,,,,,,1.6,0.9,1.3,1"));  // GPS: 5 used
+    feedLine(p, nmea("GNGSA,A,3,,,,,,,,,,,,,1.6,0.9,1.3,4"));    // BeiDou: none
+    for (auto& s : p.state().satellites) {
+        bool expected = s.system == Constellation::Gps && s.prn == 5;
+        TEST_ASSERT_EQUAL(expected, s.used);
+    }
+}
+
+void test_split_feeds_and_noise_are_handled() {
+    NmeaParser p;
+    std::string a = "garbage\r\n" + nmea("GNGGA,123519.00,5050.8136,N,00421.1532,E,1,09,0.9,61.4,M,46.9,M,,");
+    std::string b = "\r\n";
+    p.feed(a.data(), 20);
+    p.feed(a.data() + 20, a.size() - 20);
+    TEST_ASSERT_FALSE(p.state().positionValid);  // no line end yet
+    p.feed(b.data(), b.size());
+    TEST_ASSERT_TRUE(p.state().positionValid);
+}
+
+void test_an_overlong_line_is_dropped() {
+    NmeaParser p;
+    std::string junk(300, 'x');
+    junk += "\r\n";
+    p.feed(junk.data(), junk.size());
+    feedLine(p, nmea("GNGGA,123519.00,5050.8136,N,00421.1532,E,1,09,0.9,61.4,M,46.9,M,,"));
+    TEST_ASSERT_TRUE(p.state().positionValid);
+}
+
+void test_every_complete_line_reaches_the_echo() {
+    NmeaParser p;
+    std::vector<std::string> seen;
+    p.onLine = [&](const std::string& l) { seen.push_back(l); };
+    std::string data = "$GNVTG,,,,,,,,,N*2E\r\nbroken\r\n$GN";
+    p.feed(data.data(), data.size());
+    TEST_ASSERT_EQUAL(2, static_cast<int>(seen.size()));
+    TEST_ASSERT_EQUAL_STRING("$GNVTG,,,,,,,,,N*2E", seen[0].c_str());
+    TEST_ASSERT_EQUAL_STRING("broken", seen[1].c_str());
+}
+
+void test_constellation_names() {
+    TEST_ASSERT_EQUAL_STRING("GPS", constellationName(Constellation::Gps));
+    TEST_ASSERT_EQUAL_STRING("Galileo", constellationName(Constellation::Galileo));
+    TEST_ASSERT_EQUAL_STRING("BeiDou", constellationName(Constellation::BeiDou));
+}
+
+int main() {
+    UNITY_BEGIN();
+    RUN_TEST(test_checksum_is_verified);
+    RUN_TEST(test_no_fix_as_captured_indoors);
+    RUN_TEST(test_rmc_with_a_fix_gives_position_time_speed_course);
+    RUN_TEST(test_southern_and_western_hemispheres_are_negative);
+    RUN_TEST(test_utc_seconds_from_the_fix_time);
+    RUN_TEST(test_gga_gives_fix_quality_altitude_satellites_and_hdop);
+    RUN_TEST(test_fix_type_comes_from_gsa_mode);
+    RUN_TEST(test_losing_the_fix_drops_the_position);
+    RUN_TEST(test_gsv_sequence_spans_several_messages);
+    RUN_TEST(test_each_constellation_keeps_its_own_satellites);
+    RUN_TEST(test_a_satellite_on_two_bands_counts_once_with_the_stronger_signal);
+    RUN_TEST(test_an_empty_gsv_clears_that_constellation);
+    RUN_TEST(test_gsa_marks_the_satellites_used_per_system);
+    RUN_TEST(test_split_feeds_and_noise_are_handled);
+    RUN_TEST(test_an_overlong_line_is_dropped);
+    RUN_TEST(test_every_complete_line_reaches_the_echo);
+    RUN_TEST(test_constellation_names);
+    return UNITY_END();
+}

test/test_ota/test_ota.cpp

@@ -0,0 +1,329 @@
+#include <unity.h>
+
+#include <cstring>
+#include <string>
+#include <vector>
+
+#include "probation.h"
+#include "safe_mode.h"
+#include "sha256.h"
+#include "update_parser.h"
+#include "version_compare.h"
+
+using namespace roro;
+
+void setUp() {}
+void tearDown() {}
+
+// ---- helpers ----------------------------------------------------------------
+
+static std::string hex(const uint8_t* d, size_t n) {
+    static const char* h = "0123456789abcdef";
+    std::string s;
+    for (size_t i = 0; i < n; i++) {
+        s += h[d[i] >> 4];
+        s += h[d[i] & 15];
+    }
+    return s;
+}
+
+// Accepts a signature equal to the first bytes of the digest it is asked about ("signed" by us).
+struct FakeVerifier : SignatureVerifier {
+    bool verify(const uint8_t digest[32], const uint8_t* sig, size_t len) override {
+        calls++;
+        return len == 8 && std::memcmp(digest, sig, 8) == 0;
+    }
+    int calls = 0;
+};
+
+struct MemorySink : UpdateSink {
+    bool begin(size_t size) override {
+        began = true;
+        expected = size;
+        return true;
+    }
+    bool write(const uint8_t* d, size_t n) override {
+        data.insert(data.end(), d, d + n);
+        return true;
+    }
+    bool finish() override { return finished = true; }
+    void abort() override { aborted = true; }
+    bool began = false, finished = false, aborted = false;
+    size_t expected = 0;
+    std::vector<uint8_t> data;
+};
+
+// Builds an Update File the way make_ota.py does, signing with FakeVerifier's scheme.
+static std::vector<uint8_t> makeFile(const std::string& version, const std::vector<uint8_t>& image, bool goodSig = true) {
+    std::vector<uint8_t> h(update::kHeaderSize, 0);
+    std::memcpy(h.data(), update::kMagic, 8);
+    h[8] = update::kFormat & 0xFF;
+    h[10] = update::kHeaderSize & 0xFF;
+    h[11] = update::kHeaderSize >> 8;
+    uint32_t n = static_cast<uint32_t>(image.size());
+    for (int i = 0; i < 4; i++) h[12 + i] = (n >> (8 * i)) & 0xFF;
+    Sha256::hash(image.data(), image.size(), &h[16]);
+    std::strncpy(reinterpret_cast<char*>(&h[48]), version.c_str(), 31);
+    uint8_t digest[32];
+    Sha256::hash(h.data(), update::kSignedBytes, digest);
+    h[80] = 8;
+    std::memcpy(&h[82], digest, 8);
+    if (!goodSig) h[82] ^= 0xFF;
+    h.insert(h.end(), image.begin(), image.end());
+    return h;
+}
+
+static std::vector<uint8_t> image(size_t n) {
+    std::vector<uint8_t> v(n);
+    for (size_t i = 0; i < n; i++) v[i] = static_cast<uint8_t>(i * 7 + 3);
+    return v;
+}
+
+// ---- SHA-256 ----------------------------------------------------------------
+
+void test_sha256_known_vectors() {
+    uint8_t d[32];
+    Sha256::hash(reinterpret_cast<const uint8_t*>(""), 0, d);
+    TEST_ASSERT_EQUAL_STRING("e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855", hex(d, 32).c_str());
+    Sha256::hash(reinterpret_cast<const uint8_t*>("abc"), 3, d);
+    TEST_ASSERT_EQUAL_STRING("ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad", hex(d, 32).c_str());
+    const char* two = "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq";
+    Sha256::hash(reinterpret_cast<const uint8_t*>(two), std::strlen(two), d);
+    TEST_ASSERT_EQUAL_STRING("248d6a61d20638b8e5c026930c3e6039a33ce45964ff2167f6ecedd419db06c1", hex(d, 32).c_str());
+}
+
+void test_sha256_streaming_matches_one_shot() {
+    auto img = image(1000);
+    uint8_t a[32], b[32];
+    Sha256::hash(img.data(), img.size(), a);
+    Sha256 s;
+    for (size_t i = 0; i < img.size(); i += 37) s.update(img.data() + i, std::min<size_t>(37, img.size() - i));
+    s.finish(b);
+    TEST_ASSERT_EQUAL_MEMORY(a, b, 32);
+}
+
+// ---- parser -----------------------------------------------------------------
+
+void test_valid_file_in_one_chunk_is_installed() {
+    FakeVerifier v;
+    MemorySink sink;
+    auto img = image(5000);
+    auto file = makeFile("v0.3.0", img);
+    UpdateParser p(v, sink, 100000, "v0.2.1");
+    p.feed(file.data(), file.size());
+    TEST_ASSERT_TRUE(p.end());
+    TEST_ASSERT_EQUAL(static_cast<int>(UpdateParser::State::Done), static_cast<int>(p.state()));
+    TEST_ASSERT_TRUE(sink.finished);
+    TEST_ASSERT_TRUE(sink.data == img);
+    TEST_ASSERT_EQUAL_STRING("v0.3.0", p.version().c_str());
+    TEST_ASSERT_FALSE(p.isDowngrade());
+}
+
+void test_valid_file_byte_by_byte() {
+    FakeVerifier v;
+    MemorySink sink;
+    auto img = image(700);
+    auto file = makeFile("v0.3.0", img);
+    UpdateParser p(v, sink, 100000, "v0.2.1");
+    for (auto b : file) p.feed(&b, 1);
+    TEST_ASSERT_TRUE(p.end());
+    TEST_ASSERT_TRUE(sink.data == img);
+}
+
+void test_progress_counts_image_bytes() {
+    FakeVerifier v;
+    MemorySink sink;
+    auto file = makeFile("v0.3.0", image(1000));
+    UpdateParser p(v, sink, 100000, "v0.2.1");
+    p.feed(file.data(), update::kHeaderSize + 250);
+    TEST_ASSERT_EQUAL(25, p.percent());
+}
+
+void test_complete_once_the_declared_image_size_has_arrived() {
+    FakeVerifier v;
+    MemorySink sink;
+    auto file = makeFile("v0.3.0", image(300));
+    UpdateParser p(v, sink, 100000, "v0.2.1");
+    p.feed(file.data(), file.size() - 1);
+    TEST_ASSERT_FALSE(p.complete());
+    p.feed(file.data() + file.size() - 1, 1);
+    TEST_ASSERT_TRUE(p.complete());
+    TEST_ASSERT_TRUE(p.end());
+}
+
+void test_not_an_update_file_is_refused_before_writing() {
+    FakeVerifier v;
+    MemorySink sink;
+    auto file = makeFile("v0.3.0", image(100));
+    file[0] = 'X';
+    UpdateParser p(v, sink, 100000, "v0.2.1");
+    p.feed(file.data(), file.size());
+    TEST_ASSERT_EQUAL(static_cast<int>(UpdateParser::State::Failed), static_cast<int>(p.state()));
+    TEST_ASSERT_FALSE(sink.began);
+    TEST_ASSERT_FALSE(p.error().empty());
+}
+
+void test_bad_signature_is_refused_before_writing() {
+    FakeVerifier v;
+    MemorySink sink;
+    auto file = makeFile("v0.3.0", image(100), false);
+    UpdateParser p(v, sink, 100000, "v0.2.1");
+    p.feed(file.data(), file.size());
+    TEST_ASSERT_EQUAL(static_cast<int>(UpdateParser::State::Failed), static_cast<int>(p.state()));
+    TEST_ASSERT_FALSE(sink.began);
+    TEST_ASSERT_TRUE(p.error().find("signature") != std::string::npos);
+}
+
+void test_tampered_version_breaks_the_signature() {
+    FakeVerifier v;
+    MemorySink sink;
+    auto file = makeFile("v0.3.0", image(100));
+    file[48 + 3] = '9';  // v0.3.0 -> v0.9.0 after signing
+    UpdateParser p(v, sink, 100000, "v0.2.1");
+    p.feed(file.data(), file.size());
+    TEST_ASSERT_EQUAL(static_cast<int>(UpdateParser::State::Failed), static_cast<int>(p.state()));
+}
+
+void test_corrupted_image_is_aborted_at_the_end() {
+    FakeVerifier v;
+    MemorySink sink;
+    auto file = makeFile("v0.3.0", image(500));
+    file[update::kHeaderSize + 123] ^= 1;
+    UpdateParser p(v, sink, 100000, "v0.2.1");
+    p.feed(file.data(), file.size());
+    TEST_ASSERT_FALSE(p.end());
+    TEST_ASSERT_TRUE(sink.aborted);
+    TEST_ASSERT_FALSE(sink.finished);
+}
+
+void test_truncated_file_is_aborted() {
+    FakeVerifier v;
+    MemorySink sink;
+    auto file = makeFile("v0.3.0", image(500));
+    UpdateParser p(v, sink, 100000, "v0.2.1");
+    p.feed(file.data(), file.size() - 10);
+    TEST_ASSERT_FALSE(p.end());
+    TEST_ASSERT_TRUE(sink.aborted);
+}
+
+void test_trailing_bytes_are_refused() {
+    FakeVerifier v;
+    MemorySink sink;
+    auto file = makeFile("v0.3.0", image(100));
+    file.push_back(0);
+    UpdateParser p(v, sink, 100000, "v0.2.1");
+    p.feed(file.data(), file.size());
+    TEST_ASSERT_FALSE(p.end());
+    TEST_ASSERT_FALSE(sink.finished);
+}
+
+void test_image_larger_than_the_slot_is_refused_before_writing() {
+    FakeVerifier v;
+    MemorySink sink;
+    auto file = makeFile("v0.3.0", image(2000));
+    UpdateParser p(v, sink, 1000, "v0.2.1");
+    p.feed(file.data(), file.size());
+    TEST_ASSERT_EQUAL(static_cast<int>(UpdateParser::State::Failed), static_cast<int>(p.state()));
+    TEST_ASSERT_FALSE(sink.began);
+}
+
+void test_downgrade_is_flagged_but_allowed() {
+    FakeVerifier v;
+    MemorySink sink;
+    auto file = makeFile("v0.2.0", image(100));
+    UpdateParser p(v, sink, 100000, "v0.2.1");
+    p.feed(file.data(), file.size());
+    TEST_ASSERT_TRUE(p.end());
+    TEST_ASSERT_TRUE(p.isDowngrade());
+}
+
+// ---- versions ---------------------------------------------------------------
+
+void test_version_comparison() {
+    TEST_ASSERT_TRUE(versionOlder("v0.2.0", "v0.2.1"));
+    TEST_ASSERT_TRUE(versionOlder("v0.9.9", "v0.10.0"));
+    TEST_ASSERT_TRUE(versionOlder("v0.2.1", "v1.0.0"));
+    TEST_ASSERT_FALSE(versionOlder("v0.2.1", "v0.2.1"));
+    TEST_ASSERT_FALSE(versionOlder("v0.3.0", "v0.2.1"));
+    // build suffixes from git describe compare on the release part
+    TEST_ASSERT_FALSE(versionOlder("v0.2.1-3-gabc1234", "v0.2.1"));
+    TEST_ASSERT_TRUE(versionOlder("v0.2.1-3-gabc1234-dirty", "v0.3.0"));
+    // unknown versions are never called older
+    TEST_ASSERT_FALSE(versionOlder("unknown", "v0.2.1"));
+    TEST_ASSERT_FALSE(versionOlder("v0.2.1", "4c0be89"));
+}
+
+// ---- probation --------------------------------------------------------------
+
+static int judge(uint32_t up, bool frame, bool configured, bool connected) {
+    return static_cast<int>(Probation::judge(up, frame, configured, connected));
+}
+static const int kWait = static_cast<int>(Probation::Verdict::Wait);
+static const int kConfirm = static_cast<int>(Probation::Verdict::Confirm);
+static const int kRollBack = static_cast<int>(Probation::Verdict::RollBack);
+
+void test_probation_waits_30_seconds_and_a_first_frame() {
+    TEST_ASSERT_EQUAL(kWait, judge(29999, true, false, false));
+    TEST_ASSERT_EQUAL(kWait, judge(60000, false, false, false));
+    TEST_ASSERT_EQUAL(kConfirm, judge(30000, true, false, false));
+}
+
+void test_probation_needs_wifi_when_it_is_configured() {
+    TEST_ASSERT_EQUAL(kWait, judge(60000, true, true, false));
+    TEST_ASSERT_EQUAL(kConfirm, judge(60000, true, true, true));
+}
+
+void test_probation_rolls_back_when_wifi_never_comes() {
+    TEST_ASSERT_EQUAL(kWait, judge(179999, true, true, false));
+    TEST_ASSERT_EQUAL(kRollBack, judge(180000, true, true, false));
+    TEST_ASSERT_EQUAL(kConfirm, judge(500000, true, false, false));  // no Wi-Fi configured: fine
+}
+
+void test_rollback_at_boot_after_an_unconfirmed_start() {
+    TEST_ASSERT_FALSE(Probation::rollBackAtBoot(true, 0));   // first start of new firmware
+    TEST_ASSERT_TRUE(Probation::rollBackAtBoot(true, 1));    // it died before confirming
+    TEST_ASSERT_FALSE(Probation::rollBackAtBoot(false, 3));  // confirmed firmware: never
+}
+
+void test_safe_mode_after_three_crashes_in_a_row() {
+    int crashes = 0;
+    crashes = SafeMode::countAtBoot(true, crashes);
+    crashes = SafeMode::countAtBoot(true, crashes);
+    TEST_ASSERT_FALSE(SafeMode::active(crashes));
+    crashes = SafeMode::countAtBoot(true, crashes);
+    TEST_ASSERT_TRUE(SafeMode::active(crashes));
+}
+
+void test_safe_mode_count_restarts_after_a_normal_start() {
+    int crashes = SafeMode::countAtBoot(true, 2);
+    TEST_ASSERT_TRUE(SafeMode::active(crashes));
+    crashes = SafeMode::countAtBoot(false, crashes);  // e.g. `reboot` from the Debug Console
+    TEST_ASSERT_EQUAL(0, crashes);
+    TEST_ASSERT_FALSE(SafeMode::active(crashes));
+}
+
+int main() {
+    UNITY_BEGIN();
+    RUN_TEST(test_sha256_known_vectors);
+    RUN_TEST(test_sha256_streaming_matches_one_shot);
+    RUN_TEST(test_valid_file_in_one_chunk_is_installed);
+    RUN_TEST(test_valid_file_byte_by_byte);
+    RUN_TEST(test_progress_counts_image_bytes);
+    RUN_TEST(test_complete_once_the_declared_image_size_has_arrived);
+    RUN_TEST(test_not_an_update_file_is_refused_before_writing);
+    RUN_TEST(test_bad_signature_is_refused_before_writing);
+    RUN_TEST(test_tampered_version_breaks_the_signature);
+    RUN_TEST(test_corrupted_image_is_aborted_at_the_end);
+    RUN_TEST(test_truncated_file_is_aborted);
+    RUN_TEST(test_trailing_bytes_are_refused);
+    RUN_TEST(test_image_larger_than_the_slot_is_refused_before_writing);
+    RUN_TEST(test_downgrade_is_flagged_but_allowed);
+    RUN_TEST(test_version_comparison);
+    RUN_TEST(test_probation_waits_30_seconds_and_a_first_frame);
+    RUN_TEST(test_probation_needs_wifi_when_it_is_configured);
+    RUN_TEST(test_probation_rolls_back_when_wifi_never_comes);
+    RUN_TEST(test_rollback_at_boot_after_an_unconfirmed_start);
+    RUN_TEST(test_safe_mode_after_three_crashes_in_a_row);
+    RUN_TEST(test_safe_mode_count_restarts_after_a_normal_start);
+    return UNITY_END();
+}

test/test_settings/test_settings.cpp

@@ -26,6 +26,8 @@ void test_defaults_when_store_is_empty() {
     TEST_ASSERT_TRUE(s.getBool(Setting::Sound));
     TEST_ASSERT_TRUE(s.getBool(Setting::ProbeMacRaw));
     TEST_ASSERT_TRUE(s.getBool(Setting::WifiEnabled));
+    TEST_ASSERT_TRUE(s.getBool(Setting::GnssEnabled));     // Q58: on by default
+    TEST_ASSERT_FALSE(s.getBool(Setting::CoordinatesDms));  // Q64: decimal degrees
     TEST_ASSERT_EQUAL_STRING("EU868", s.getString(Setting::Region).c_str());
     TEST_ASSERT_EQUAL_STRING("CET-1CEST,M3.5.0,M10.5.0/3", s.getString(Setting::Timezone).c_str());
 }

test/test_settings_menu/test_settings_menu.cpp

@@ -107,6 +107,19 @@ void test_names_are_text_rows_with_their_byte_limits() {
     TEST_ASSERT_EQUAL_STRING("RORO", f.menu.value(shortName).c_str());
 }
 
+void test_gnss_and_coordinate_rows_toggle() {
+    Fixture f;
+    int gnss = f.row(SettingsMenu::Row::Gnss), coords = f.row(SettingsMenu::Row::Coordinates);
+    TEST_ASSERT_EQUAL_STRING("On", f.menu.value(gnss).c_str());
+    TEST_ASSERT_EQUAL_STRING("Decimal", f.menu.value(coords).c_str());
+    f.menu.toggle(gnss);
+    f.menu.toggle(coords);
+    TEST_ASSERT_FALSE(f.settings.getBool(Setting::GnssEnabled));
+    TEST_ASSERT_TRUE(f.settings.getBool(Setting::CoordinatesDms));
+    TEST_ASSERT_EQUAL_STRING("Off", f.menu.value(gnss).c_str());
+    TEST_ASSERT_EQUAL_STRING("Deg min sec", f.menu.value(coords).c_str());
+}
+
 int main() {
     UNITY_BEGIN();
     RUN_TEST(test_every_row_has_a_label);
@@ -118,5 +131,6 @@ int main() {
     RUN_TEST(test_brightness_steps_with_left_right_within_bounds);
     RUN_TEST(test_wifi_is_a_page);
     RUN_TEST(test_names_are_text_rows_with_their_byte_limits);
+    RUN_TEST(test_gnss_and_coordinate_rows_toggle);
     return UNITY_END();
 }

test/test_track/test_track.cpp

@@ -0,0 +1,78 @@
+#include <unity.h>
+
+#include <string>
+
+#include "track.h"
+
+using namespace roro::gnss;
+
+void setUp() {}
+void tearDown() {}
+
+void test_distance_is_haversine() {
+    // One minute of latitude is one nautical mile.
+    TEST_ASSERT_FLOAT_WITHIN(2.0, 1852.0, distanceMeters(50.0, 4.0, 50.0 + 1.0 / 60, 4.0));
+    TEST_ASSERT_FLOAT_WITHIN(0.01, 0.0, distanceMeters(50.0, 4.0, 50.0, 4.0));
+    // A degree of longitude shrinks with latitude: cos(60°) = 0.5.
+    TEST_ASSERT_FLOAT_WITHIN(60.0, 55597.0, distanceMeters(60.0, 0.0, 60.0, 1.0));
+}
+
+void test_first_point_is_always_recorded() {
+    TrackRule rule;
+    TEST_ASSERT_TRUE(rule.due(1000, 50.0, 4.0));
+}
+
+void test_a_point_needs_5_seconds_and_5_metres() {
+    TrackRule rule;
+    rule.due(0, 50.0, 4.0);
+    double tenMetres = 10.0 / 111195.0;  // degrees of latitude
+    TEST_ASSERT_FALSE(rule.due(4999, 50.0 + tenMetres, 4.0));  // too soon
+    TEST_ASSERT_FALSE(rule.due(5000, 50.0 + 1e-6, 4.0));       // too close (standing still)
+    TEST_ASSERT_TRUE(rule.due(5000, 50.0 + tenMetres, 4.0));
+    TEST_ASSERT_FALSE(rule.due(6000, 50.0 + 3 * tenMetres, 4.0));  // 5 s from the last point
+    TEST_ASSERT_TRUE(rule.due(10000, 50.0 + 3 * tenMetres, 4.0));
+}
+
+void test_reset_starts_over() {
+    TrackRule rule;
+    rule.due(0, 50.0, 4.0);
+    rule.reset();
+    TEST_ASSERT_TRUE(rule.due(100, 50.0, 4.0));
+}
+
+void test_file_name_from_utc() {
+    TEST_ASSERT_EQUAL_STRING("/gnss/tracks/20261004-203447.gpx", trackPath(1791146087LL).c_str());  // 20:34:47 UTC
+}
+
+void test_gpx_header_point_and_footer() {
+    std::string h = gpx::header("20261004-203447");
+    TEST_ASSERT_TRUE(h.find("<?xml version=\"1.0\" encoding=\"UTF-8\"?>") == 0);
+    TEST_ASSERT_TRUE(h.find("<gpx version=\"1.1\" creator=\"roro9stack\"") != std::string::npos);
+    TEST_ASSERT_TRUE(h.find("<name>20261004-203447</name>") != std::string::npos);
+    TEST_ASSERT_TRUE(h.find("<trkseg>") != std::string::npos);
+    TEST_ASSERT_EQUAL_STRING(
+        "<trkpt lat=\"50.8692030\" lon=\"-4.2535070\"><ele>42.5</ele><time>2026-10-04T20:34:47Z</time></trkpt>",
+        gpx::point(50.869203, -4.253507, true, 42.5f, 1791146087LL).c_str());
+    TEST_ASSERT_EQUAL_STRING("<trkpt lat=\"50.8692030\" lon=\"4.2535070\"><time>2026-10-04T20:34:47Z</time></trkpt>",
+                             gpx::point(50.869203, 4.253507, false, 0, 1791146087LL).c_str());
+    TEST_ASSERT_EQUAL_STRING("</trkseg></trk></gpx>", gpx::footer().c_str());
+}
+
+void test_an_unfinished_file_is_recognised() {
+    TEST_ASSERT_TRUE(gpx::finished("...<time>x</time></trkpt>\n</trkseg></trk></gpx>\n"));
+    TEST_ASSERT_TRUE(gpx::finished("</trkseg></trk></gpx>"));
+    TEST_ASSERT_FALSE(gpx::finished("...<time>x</time></trkpt>\n"));
+    TEST_ASSERT_FALSE(gpx::finished(""));
+}
+
+int main() {
+    UNITY_BEGIN();
+    RUN_TEST(test_distance_is_haversine);
+    RUN_TEST(test_first_point_is_always_recorded);
+    RUN_TEST(test_a_point_needs_5_seconds_and_5_metres);
+    RUN_TEST(test_reset_starts_over);
+    RUN_TEST(test_file_name_from_utc);
+    RUN_TEST(test_gpx_header_point_and_footer);
+    RUN_TEST(test_an_unfinished_file_is_recognised);
+    return UNITY_END();
+}