wilbowes/EchoMuse emos-v0.7

emOS emos-v0.7

on GitHub

emOS v0.7

The device knows its own name.

What changed

emOS reads the serial from /proc/idme/serial — Amazon's ID Manager, exported
by the kernel and readable without a property service or a bootloader argument.
The console prompt now reads root@em-G090LF... instead of root@android,
which is how you tell two Echoes apart over USB.

It matters on amonet 2.x because the old source was not reliably there to read.
FireOS 6 boots a 32-bit kernel, so the kernel's command line is capped at 1024
bytes; LK wraps our image's cmdline with 421 bytes in front and 344 behind, and
ours is 385 against stock's 70. That is 1150 bytes, and androidboot.serialno
starts at byte 1040 — cut off before the kernel ever sees it. FireOS 5 boots
aarch64, where the cap is 2048 and the same string fits, which is why this
looked like an amonet 2.x problem rather than a length one.

The kernel cmdline stays as a fallback and is logged when used. It is the one
source that can be silently WRONG rather than absent: a value cut mid-truncation
is short but well formed, and there is no way to tell it from a serial that
legitimately sits last on the line.

A serial that is not printable ASCII is rejected rather than used. This is an
identity, and a plausible-looking wrong one is worse than none.

Upgrading

Re-run the provisioning wizard's build and flash steps. Nothing on /data is
touched, so your WiFi and console password survive.

Known issues in this release

• This does not fix devices registering as unknown-device. That is the
  firmware's serial, not emOS's, and it ships in device v2.16.0. emOS uses the
  serial only for the hostname.
• WiFi on FireOS 6 with a WPA3 or mixed WPA2/WPA3 network does not work and
  cannot: the driver has no SAE and the kernel is too old for us to do it in
  userspace. Set the network to WPA2. em-wifi marks such networks
  (WPA3 - not supported) rather than offering them (#536).
• emOS written to boot_b on an amonet v2.0.0 device has been reported not to
  boot, with the same image booting from boot_a (#544). Under investigation.

Checksums

Verify the assets against the release page before flashing anything.

What's Changed

• Cache OWW models per device_id instead of rebuilding on every reconnect (#512) by @scragnog in #528
• Give the writing rules a frequency budget by @wilbowes in #537
• Say what the writing rules are aiming at by @wilbowes in #538
• Release controller-ea 2.24.0-ea.5 by @wilbowes in #539
• Let the connect step read what the device can actually tell it (#517) by @wilbowes in #540
• Read the serial from idme, where the hardware keeps it by @wilbowes in #542
• Read system_part off the build POST, so the image carries its /system stamp by @wilbowes in #548
• Refuse a wake threshold that cannot fire, at the write path by @wilbowes in #549
• Let a mic gain of 0 reach the codec by @wilbowes in #551

New Contributors

• @scragnog made their first contribution in #528

Full Changelog: emos-v0.6...emos-v0.7