i4 got wet and home button stopped working, since no iphone5 I decided to fix the 4.
took 2 hours, tiny little screws! just to get to the home button, one has to disassemble the whole phone.
make sure you have a sheet of paper and write down each screw's size and location.
before you put the whole phone back together completely, do a test run in-case you didn't attach one of those tiny little connectors just right.