Chosen Solution
Suddenly and for no apparent reason my home button has stopped working. tried sorting the 2 home button plugs but still didn’t respond. i replaced the whole flex(charging,mic, etc) from an old iphone 5 i had on my self which i’m sure that the home button was working and i still get the same results. before the home button stopped working the device went in recovery mode a couple of times but booted normally after reboot. of course i have also tried restoring the device and now it’s stuck in “press home to open” screen. is there any chance it’s a logic board issue? any help would be much appreciated. thanks in advance.
Based on your troubleshooting, I would suspect a logic board issue as well. Do thorough visual inspection of the Dock connector on the logic board and it’s surrounding area. You may have a broken or damaged pin or debris causing a faulty electrical contact. If that is okay, then I would check to see if U3 is not damaged. It is on the edge of the board and can be damaged when prying a battery out of the phone. Perhaps this is a latent problem from a previous battery replacement. Also check FL5, a small SMD filter on the logic board, if you are so inclined. It should appear as a short when probed with a multimeter. If it is missing or reading a higher resistance than ~0, it would impede the Home button signal to the CPU. That is essentially the circuit involved for the Home button. The iPhone 5 is a fairly old device so it may not be worthwhile to you to have it repaired, but an experienced micro-solderer should be able to fix this.
