Home button iPhone4 and battery iPhone5

My Problem

Home button didn't answer.

iPhone 5 switched of at 25% charge.

My Fix

Home button was a complete disassamble of the iPhone4, 1 screw was left over (2nd fixation of speaker), but now works great again.

Battery exchange did not bring any change. Must be a main board defect.

My Advice

Order an additional holder for all the screws with a size of a flyspeck.