I can only speak for the iPhone 8 at this point, but I have no reason to believe it would be different for the iPhone 8 Plus. The camera and flash ARE synced on an iPhone 8. If the camera isn’t working, neither will the flash. One more note regarding iPhone 8: There is one screw on the logic board that is covered by a rubber pad. You need to scrape/remove that rubber pad to access the screw. In my situation, some of that rubber residue ended up blocking the camera contact on the logic board which prevented it from securely connecting. If anyone is experiencing similar issue after disassembling an iPhone 8, this is worth checking out.