I replaced my battery in my iPhone and thought problem solved. Then I realized home button not working. After trying all the stuff online and with no success I reopened my iPhone and noticed that I had bent down the two gold contacts while I was trying to pull my battery out. You'll see them just below battery. I took a very small sewing needle and pried them up. The problem was they weren't making contact with home button contacts on screen side of phone. All fixed!