if the head unit is in fact a n1, ground the parking brake wire and force install 40 series discs. turn the unit off and push eject + reset at the same time then press up right up right down right down right enter"push joystick in" this will give u the hidden menu for the unit. this works for the n1 have no clue bout the n2 or n3 head units. u will have to look for a force write menu and clear the gps, ram, and basically all u can before force writing the 40 discs. otherwise u have to solder to watch video and drive.
