Replaced iPhone 8 Battery, Now Home Button is Dead My battery life was getting pretty poor, but my phone was fully functional otherwise. So I ordered a new one on ifixit it and replaced it.
It was not the first iPhone battery I've replaced and it was pretty easy to do. But when I reassembled it, the home button is now dead. Dead in every way. It doesn't perform any function when you push it, it doesn't read you fingerprint, and it gives no taptic feedback.
Important to note, I did not disconnect any of that stuff to do the battery. I dislodged the screen, tipped it up, and easily did the battery without taking all those parts out.
I did turn the phone on before reinstalling the display. I read afterwards that that can disable the home button on older iPhones, but I'm not sure if that applies to the 8.
I did take the phone apart again, twice. Checked all connectors, they're all great. Theres nothing obvious I can see. I did several hard resets, no affect. I also removed the battery again for a few minutes to fully reset the device.
Any other ideas what could have happened, and how I can try to fix?
You have a couple options.  For diagnosing the issue you could buy a new display to see if that is the issue, or buy a new home button called the JC home button.  It will not restore Touch ID, but it will tell you if the screen cables are broken, or the home button itself.
Before you do any of that, try using the old battery again to see if your home button works again.  Also take off the display and reseat the display cables.
I have replaced several batteries on iPhones and have never had that issue, so I'm guessing a cable isn't seated correctly or a ribbon wire got torn.