Ever since I updated to iOS4, sometimes when I hang up from a phonecall I will get a black screen with just the top carrier logo, time and battery icon left at the top. The phone does not respond until I lock it then unlock it. I tried doing a DFU restore but it still does it.
Also I have just noticed that when this happens, if I double tap the home button, I get a line appearing where the active apps normally appear:
I am able to take screenshots and use the sleep button which brings the home screen back. Do you think it is something to do with the O2 auto balance notification?
