for the AVICD2, while the unit is in normal operation with the ACC and 12V powered up, hold the open button so that the DVD eject button is revealed, then press the reset button in with a paper clip, and HOLD the DVD eject button. Continue to hold the DVD eject button and release the RESET button. The unit will power up and say somthing about hitting reset. Instead of doing that, press the 'open' key so that you can see the screen again and then enter the super-secret code "UP - UP - DOWN - DOWN - SELECT" using the joystick thing. It will boot into a special service menu.