ADR 0006 No OTA

Snapshot of docs/decisions/0006-no-ota.md at commit 707b4a0, preserved before the docs were compacted. History only: the current specs are in the repository.

0006 No OTA firmware updates for now

Date: 2026-10-26 · Status: accepted · Supersedes the OTA part of 0002

Context

0002 planned firmware updates over the air: two OTA app slots, an ota.* config API, a relay from the central to the peripherals over ESP-NOW, rollback and an update service in the app (issues #15–#18, milestone "OTA"). Firmware 2.9 (programFormat 3) uses 85 % of the single 2 MB app slot (1 789 868 bytes). Two OTA slots on the 4 MB flash would be about 1.9 MB each, and SPIFFS for the programs would shrink to a few hundred KB, with no room for growth.

Decision

• No OTA firmware updates in the foreseeable future. Pods are flashed over USB (pio run -d firmware -e NewBoard -t upload, then -t uploadfs for the programs).
• The partition table keeps its single app slot. Space goes to firmware features and programs.
• Issues #15, #16, #17, #18 and the "OTA" milestone are closed as not planned.
• The version streams and the release workflow from 0002 stay. A firmware release still publishes the binaries, also on Pages, for a possible browser-based USB flasher.

Consequences

• Updating a set means connecting every pod to a computer once per firmware release.
• The app's "firmware update needed" hints mean a USB flash.
• If OTA returns, it needs a new ADR, a size budget (for example -Os, lower log levels, NimBLE instead of Bluedroid) and one USB flash of every pod for the new partition table.