I recently ran into a problem at work. I changed a battery in a vehicle that had this radio.  When I went to pull it out of my bay I was greeted with a password lock on screen.  So I took to searching Google and came across a post on avic411.

In that post they had a script that you load onto a SD card and install into the radio.

Follow the instructions and you are good to go. If the post every goes down here is a link to the files.  Link

Hope this helps someone out the way it did me.