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.