Hi,
The menu you need to enter into is the "secret" service menu. I have an X1 (Europe's version of the N1), so I am not positive if you enter the menu in the same way, but for the X1, this is how you enter into it:
Remove any disk's from the headunit.
Hold reset and eject together, then release the reset button but continue to hold eject.
The screen will go in and the come back out. The screen will now say to press the reset button - DO FOLLOW THIS PROMPT.
Then with joystick, follow this, by moving the joystick in the directions below:
Up, Right, Up, Right, Down, Righ