Reboot if stuck (hanged)
MODE + LAP
Clearing non-volatile settings
The unit must be turned off. Press and hold the LAP/RESET button then press and release the POWER button to turn the unit on. Now press and hold the ENTER and MODE buttons while continuing to hold the LAP/RESET button. Release the LAP/RESET button and the unit will reboot (it will look like it turns off). Wait a couple of seconds and then release the ENTER and MODE buttons. The unit will boot up again with a clear non-vol.