system error

I just bought, and have been flying, my P4 about 6 weeks now and find it extremely stable. In fact, it seems quite difficult to crash, unless of course I do something deliberate, like fly it into a wall in sport mode, or back it into a tree in "P" mode. The purpose of this thread is two-fold...

Please help, this is a nightmare! The live feed won't work, its just shows a black screen with a loading icon. I'm using: iPhone 6SE App v1.0.6 (I tried to downgrade to 1.0.56 but this failed) firmware 3.14 I've checked all the wires are plugged in correctly, I've tried rebinding the wifi...