After the removal of the headphone jack, one of the biggest changes to Apple’s iPhone 7 is the new home button: it’s no longer a mechanical button, but a force-sensitive static button. It seems that the company has introduced an additional workaround time when the new button might not work as expected.
According to a MacRumors forum user, the iPhone 7 displays a home button in the phone’s screen when it detects that there might be a problem with it.
The user noted that the phone displayed the message after it turned off while charging. When he restarted the device, "it worked at first then started spazzing out. The Haptic engine kept firing [three to four] times in a row for every 'press'. I restarted [the phone] again and it's back to not working."