The deep reset procedure depends on if it is pre-2013 (old board) or 2013+ (new “UVC” board).
On the old board you will remove both the backup battery and the main battery pack for 60 seconds then put the main battery back on first then the backup battery last.
On the new “UVC” board with the batteries plugged in you will press and hold the top button then press the bottom button on the board then release both.
BASIS V and BASIS G
The old board will confirm the reset by flashing red and green lights and giving audible sounds shortly after plugging the main battery in.
The new “UVC” board will confirm the reset by turning both red and green lights on solid for approximately 10 seconds then they will go out 15 seconds later both red and green will flash and give an audible sound.