Just swapped over to a Hero Black 4 to replace a Hero Black 3 and there is now no video from the camera. The monitor is still showing flight info from the p2 but the rest of the screen is black as if I had a lens cap on. Tried OSD on the Go Pro but that didn't help. Had the GoPro 4 set up as in Philip Bloom, with 2.7k res, medium view, 25p. Is there some incompatibility here or do I have something wrong in the set up. Go Pro 4 video looks fine but not much better than the Hero 3 black.