I did the swap in my Laramie that originally had the 8.4 with Nav. When I first swapped in the 12” screen, it was blank. I then swapped out my radio module with the one that came with the 12” screen and everything powered on. Everything works except, the volume knob, tuning knob and the screen blank button. Pushing the volume knob will still turn off the unit though. The steering wheel volume buttons still work and the on screen radio controls also work. I haven’t been able to get updated software to flash the 12” to see if that would make the knobs work or not.