twislaandClaude Opus 5.5
6b71aace4f
The SSH App opens one session to a shell, over libssh (LibSSH-ESP32 5.10.0) on mbedTLS. A server is trusted the first time on its fingerprint, and a changed key is a warning with Cancel selected. The password is typed each time and kept nowhere; or the device makes itself an Ed25519 key, whose public half is shown, written to /ssh/id_ed25519.pub and printed by `ssh status`. lib/term is the terminal: what a shell, less, top, nano and vim send, with sixteen colours, scroll regions, the alternate screen and 100 lines of scrollback. Five text sizes with Ctrl and + or -, from 60x20 to 26x8, told to the far end. The session goes on when the App is left; SSH shows in the Status Bar. `ssh user@host` in the Shell opens the App. Also: - Keys that aren't characters carry Shift, Ctrl and Alt. The terminal needs it, and it makes Ctrl+Fn+up/down in a note and Shift+Tab in Gemini work from the real keyboard. - IRC doesn't try to connect under 60 KB free: started with a session open, its TLS handshake took the heap down to 236 bytes. - libssh's own curve25519 is left out of the build (scripts/libssh_filter.py): libsodium's has the same names. Costs 292 KB of flash and about 50 KB of heap while a session is open; not started under 75 KB free. Docs: guide page, how-to, FAQ, home page, Status Bar, SD card folders, the memory how-to, README, glossary, N1 notes with Q254 to Q266 and the checks. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT
3.7 KiB
+++ title = "Updates" description = "How the device updates itself from the project's releases, from the SD card or from a PC, and how it protects itself when an update goes wrong." weight = 14 [extra] tag = "Firmware" screens = ["update.png"] +++
Every update is one signed file (.ota). The device installs only a file signed with the project's key, so it cannot be tricked into installing anything else, whichever way the file arrives.
Settings → Firmware
The page shows the version running, its status, the address to push updates to over Wi-Fi, and:
- Latest release: Enter (or c) asks the server and says
v0.11.0 (new)or(current). Enter again opens the release: its version, date, size and the tag's message, with Install when it is newer. - Older releases: the last ten, newest first. Opening an older one offers to go back to it, with a different question.
- On the SD card: the
.otafiles found in/updates, ready to install. Copy one there with a computer or the Storage App; the Storage App also opens an.otafile and says whether it would install.
An install needs Wi-Fi if it is a download. The new firmware is checked before anything is written (the signature after the first 160 bytes) and again at the end (the image's hash). Then the device restarts. It will wait up to 60 seconds if you are typing, so that a restart never eats a note.
Check for updates
Settings → Check for updates is on by default. Once a day, with Wi-Fi up and the clock set, the device looks at the latest release and says v0.11.0 is out: see Settings > Firmware, once per version. It installs nothing by itself, and it does not announce a version that already failed and rolled back on this device.
Probation and Rollback
A newly installed firmware runs on Probation: it must boot, draw its screen, start its services and run 30 seconds without a crash, and reconnect Wi-Fi if that is configured (within 3 minutes), before it is confirmed for good. If it crashes or restarts, or cannot get Wi-Fi back, the device rolls back to the previous firmware by itself and says so.
Safe Mode
If a confirmed firmware crashes and restarts 3 times in a row, the device starts in Safe Mode instead: only Wi-Fi and firmware updates, so a fix can be installed without a cable. A normal restart leaves it.
IRC steps aside
A secure connection takes about 52 KB of memory at its peak, and IRC's own takes about 40 KB of the 107 KB there is. So a check or an install that you ask for makes IRC disconnect for the few seconds it takes, and reconnect afterwards. The daily check never does that: with IRC connected it waits for a moment when IRC is not, so if IRC stays connected for days the daily check does not run, and Latest release is the way to check.
How the connection is trusted
The connection to the project's server is checked against the two root certificates that Let's Encrypt's chains end in, not against the usual bundle of about 130 authorities. Whatever the connection, the update file's own signature decides what gets installed.
For developers
Updates can also be pushed from a PC over Wi-Fi, with scripts/flash.sh --ota <ip>, or put on the card with scripts/sd_put.sh: see the README. The firmware's console can be reached over Wi-Fi too: see The Debug Console.
The keys, as the device lists them
What Fn + h shows on these screens. These tables are generated from the firmware's own lists, so they are always the current ones.
{{ keys(scopes=["firmware", "firmware-release", "firmware-older"]) }}