0007 — Recovery: TWRP on the mainline kernel first

Context

The existing TWRP build for the Note Air embeds the vendor kernel, for which no source was published, so it can't be redistributed. A custom recovery would fit our storage layout best but needs a new UI.

Decision

Pursue TWRP userspace on our mainline kernel first: publishable, all mainline storage features, adb shell as a headless path when the panel stays dark, familiar to users. It needs a display backend that hands frames to our e-ink engine. If Android's recovery init or the patch load proves unworkable, build a custom GlassineOS recovery instead.

The recovery kernel uses the same source tree with its own minimal, built-in configuration: storage, USB, display, touch, power key, battery/charger, watchdog, crash log, dm-crypt, btrfs. No Wi-Fi, Bluetooth, audio, modem/DSP or GPU, so it needs no vendor firmware. It is promoted rarely, after a hardware boot test.

Status

Accepted 2026-10-03.