My AVH 4200NEX has worked fine.  There is a backup camera installed.  This morning I went out and started the pickup and the image that appeared was the rear view with guidelines.  I could not get rid of the video.  I turned the key off and then back on, and now I get a blank screen - no Pioneer logo or disclaimer, and then the screen goes black and the rear guidelines show up.  I can't get to the main menu, or ANY menu.  The radio just sits there with the black screen and guidelines.

Radio is struck in reverse camera mode

I found a solution on YouTube.  To bypass everything and get to the menu, just press and hold the MUTE button.  Then you can go to the camera settings and turn the camera view off and check your "Reverse Gear Setting" option and try changing from "Battery" to "Ground" or vice-versa.

Like I said.....  someone mess with the setting or install error