Chosen Solution
After changing screen, the Home button, volume button and sound does not work. Everything else does seem to work just fine. Any ideas on what happened here.
The front camera flex cable on the iPhone 7 Plus seems to be very sensitive. The first thing I would check for is to make sure there is no small tears to the cable. If the cable seems to be intact, remove the front camera flex cable and ensure that the black adhesive sticker is covering the gold contact pads on the flex cable. The iPhone 7 Plus in particular seems to easily leave the sticker behind on the original screen when you go to make the swap. Here is a picture of the adhesive sticker I am referring to:
As Josh points out in Earpiece does not work after screen replacement, if this sticker is not present, it grounds out to the frame of the iPhone display causing slow boot times, no earpiece speaker, the home button may not work, etc. So definitely check for that sticker.
Taking a while to start up is classic if it’s finding a problem with any of its parts ie home button. Likely hood is if uve swapped the bits back to the original screen and still are having a problem then you might have damaged those parts when you did the replacement Try with a new front camera flex and maybe volume button flex, unfortunately the button on the 7 is set for that phone so you can’t really replace that urself look for signs of damage, try replacing the other bits first
