Just installed the HDMI board on my P3P. In fiddling with it, I've discovered that you really don't need the DJI Go app. Hook up an HDMI monitor and you get the the camera screen, the basic OSD info (battery only as a percentage), GPS signal strength, RC signal strength, altitude, speed, course, flight mode. You only get video as a recording mode (as far as I can determine) and you can't adjust the video parameters. I'm sure this comes as no surprise to pilots that have been with the Phantom class UAVs since The Olden Days but I was (pleasantly) surprised.