Split the CircuitPython firmware into a tiny stable loader (code.py) + the application (app.py,
carries APP_VERSION). The editor's ⋯ → "⬆ Update firmware" queries the device version (SysEx 0x02
-> 0x03 reply), fetches the latest app from the site (/pico-cp-app.py), shows device-vs-latest, and
pushes the new app.py over USB-MIDI (SysEx 0x20). The device installs it to a trial slot (old build
kept as app.bak), reboots, and the loader AUTO-ROLLS-BACK to app.bak if the new build fails to start;
a build that runs cleanly ~5s is confirmed (clears /trial). No BOOTSEL, no dragging; Chromium/Firefox.
app.py forced to pure ASCII so it pushes raw (no base64); SysEx buffer raised to 60KB.
build.sh/deploy.sh: bundle code.py+app.py and serve /pico-cp-app.py. Docs updated.
Verified in CPython: version reply, update install+reboot+ACK, rollback file dance; editor loads clean
with the updater wired.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
e8945ee1d1