More information about this touch screen but in iOS 8 Beta 1...
This is also a problem on my iPhone 4S. I updated my 4S to iOS 8 beta 1, and I have the following issues:
- the touch screen becomes uncalibrated
- only the left half of the screen responds to touch events
- the left half of the screen "references" the right half of the screen (e.g. touching the left hand side of the screen fires a tap event on an element on the right hand size of the screen)
- I also noticed that when I restart the phone, the touch screen works until I open an app
- the left vs. right designations above are used in reference to a vertical phone orientation. Using the phone in landscape mode does not change which side of the phone's screen is unresponsive.
This is unfortunate - I've never installed an iOS beta that was so buggy it was unusable.
I sure hope Beta 2 comes out in less than two weeks!