Backport the pinned Arduino 2.0.17 HWCDC suffix and interrupt handling into a build-local source copy. Preserve unsent bytes, serialize ISR and producer rearm, and include FIFO, suffix and active writers in transport cleanup proofs without changing the loop stack allocation.
Validate zero and short writes, producer races, quarantine and stale cleanup with sanitizer-backed native tests and negative controls. Keep other frameworks and USB modes on their existing drivers; update the watchdog file mock for the existing buffer API.
Heltec V4 timing measured 2.19 seconds for recovery checks, temporary-file cleanup, open and buffer configuration combined in one lazy-save pass. Defer those startup operations across guarded companion loops while explicit durability callers still initialize synchronously.
Track ownership only after attempting to create the temporary file, preserve unowned stale files on early cancellation, and reject premature writes or commits. Cover startup faults, interruption, mutation, cache pressure and synchronous-construction negative controls with native sanitizer tests.
Arduino defaults to 4 KiB stdio buffering, so small record writes and CRC
reads could still trigger large SPIFFS batches. Set the newly opened ESP
writer buffer to one 152-byte contact record and verifier buffer to 64
bytes before I/O. Fail closed if either setup fails; keep other platforms
unchanged.
Model backend buffering separately from logical File operations. Validate
mutation cancellation, durability, setup failures, and negative controls
which restore the hidden default writer or reader batching. Update API
seams in existing uncached, radio and telemetry fixtures.
Extend the cooperative contact transaction to uncached ESP32 storage,
including the PSRAM policy used by the XIAO and V4. Preserve owned contact
copies, the 152-byte disk format, revision cancellation and synchronous
durability operations. Keep contact capacities unchanged.
Avoid SDK error logs when optional blob or transaction cleanup files are
absent, while preserving metadata and deletion failure handling.
Validate cached ESP/nRF and uncached PSRAM paths under ASan/UBSan,
including bounded writes, mutation cancellation, faults, recovery and
reboot readback. Update the existing uncached production fixture.
Keep Companion and Terminal Chat profiles unchanged; retain full-sensor and reduced-sensor OTA builds. Add compact crypto and OTA names, qualified display asset compression, font license packaging, and scope regression tests.
mikecarper