It's possible to enable rear cam by software. Menavrus's users can use my app for that purpose but image is disabled when car reaches 30km/h. I don't know if that's a software limitation.I already used the diagnostic version a couple weeks ago to tell the car it is in parking mode, works fine!
I wonder if it is possible to open up the camera-reverse view that would be very nice! I know Tesla also have this option, you can always see the back camera even on a highway, I would love this option!