Chosen Solution
After changing the display assembly on my iPhone 6S, my HOME button doesn’t work anymore. The phone gave me an alternate way to access my home screen. I replaced the HOME screen button assembly, but it still won’t recognize that the HOME button replacement. Any suggestions out there?
I’d say you received a faulty screen/flex connector cable that is integrated into the backlight. I got one that did the same to me. Have you tried the original screen again with the home button? See if that works. If not, there is a possibility that the home button flex was damaged in the process. Good luck and keep us posted!