Chosen Solution
My phone had a lot of sand that got into the earspeaker. I opened the phone up and removed the earspeaker and cleaned it out, I didnt even disconnect the screen. When I screwed everything back in, the phone said “Unable to activate Touch ID on this phone.” I read a bit online and it said when you replace screen it will do that and the home button is linked with each screen. But I didnt even take off the screen let alone replace it, I just cleaned the earspeaker and thats it.
Sounds like the cable that acts as an extension cable to plug the home button into has gotten torn when lifting up the screen. The only way to tell is to take out the screen and disassemble with the metal plate removed and inspect the ribbon flex from the screen for physical damage.
I think not taking off the screen was a bad idea. The ear speaker is screwed onto the back of the screen, to attempt to remove sand from the ear speaker without removing the screen seems extraordinarily difficult to do with the delicate flexes still attaching the screen to the logic board.
All you can do here is first—power cycle the phone a few times just to rule that out, then get the triwing driver so you can take off the shields, disconnect the battery and then remove and reseat the screen connectors. If that doesn’t work, then you can try a new screen.
