FEL indicates that the device works in firmware flashing mode. This mode is used to flash the firmware to the device using special flashing tools. This mode can be activated from the recovery menu (FLASH). But in some cases, it can be activated automatically if something went wrong with the file system of the device.

Usually, to quit FEL mode you'll need to reboot your LaMetric (press and hold the power button for 10 seconds).

If this does not help please drop an email to support@lametric.com