Bluetooth firmware may run into a bad state on balenaFin devices

[majorz]

A fleet of balenaFin devices where both WiFi and Bluetooth are used simultaneously occasionally has devices where the Bluetooth stops functioning properly. This does not occur on the WiFi part, but only on the BT one. The error occurs randomly and not always with the same error, but always with an indication that the BT firmware is stuck or errors out:

[48958.149269] BT: host_to_card, write iomem (1) failed: -110.

In another instance of the problem bluetoothctl was not discovering the device, but hciconfig partially discovered it and exited. There was not a particular kernel error.

The workaround is rebinding the mmc bus to trigger reset and reload of the driver/firmware brings so that the Bluetooth is brought back to a functioning state:

echo 3f300000.mmcnr > /sys/bus/platform/drivers/mmc-bcm2835/unbind
sleep 2
echo 3f300000.mmcnr > /sys/bus/platform/drivers/mmc-bcm2835/bind

[jellyfish-bot]

[majorz] This issue has attached support thread https://jel.ly.fish/938a75b5-3e30-42e1-89f9-62f1183038f1