I have an F90BT with the FX3.1 update installed and have the following problem, I also had this problem before when I was on 2.0 firmware.

When I put my car in Reverse my screen goes black and says "Caution: screen image may appear reversed"

Anybody know what's wrong and how to fix it? Also please note that I DONT have a backup cam

disable the rear camera.

In the settings of the unit you need to turn rear camera OFF.

After I made this thread I figured it had something to do with the camera, so I went into settings and disabled it, and that solved my problem.

Thanks alot for your help guys