Controller turns on but screen software won't boot. I can see the backlight on the screen but it won't go further. The P4 connects and I can fly with a functioning camera but nothing on the screen. It flys like it is in beginner mode. This started as an intermittent thing. Have done a controller factory reset and it worked fine a few times but now not working for over a week. Have tried a hard reset via DJI instruction (C1, C2, shutter button together - turn off and on) but got nothing from this. Any help would be much appreciated.