Holy crap my iPhone 4 home button did not responding anymore in the last days. So like me many users are upset about it in forums. After numerous idiotic solutions I found a workaround that does work and has worked ever since. I can’t believe that but if I plug my USB charging cable into the iPhone and press the right part where it is plugged up towards the screen, just a little, bam that helped!
But Apple…wtf…the only most used mechanical button installed so bad?
An alternative solution is to activate the “AssistiveTouch” in Settings -> General -> Accessibility. This will bring up a transparent round button at the bottom right of the screen with accessibility helper especially a home button option that works just like as the physical home button.