How do I force my iPhone to factory reset?
If your power button or volume down button is broken, you may not be able to perform a hard reset on your iPhone 7 or 7 Plus. If your iPhone is still under warranty, the Apple Store may cover the cost of the repair for you. Go to Apple's support page to set up an appointment at your local Apple Store.Apr 5, 2017
How do I factory reset my iPhone 7 plus without passcode?
If a power cycle/restart does not resolve your issue, perform a soft reset. Press and hold the Volume down and Side buttons until you see the Apple logo, then release both buttons.
How do I factory reset my iPhone 7 Plus with buttons?
iPhone 7: Press and hold the Volume Down and the side button at the same time. iPhone 6S & older: Press and hold both the Side and Top buttons. Hold these down until the iTunes connection recovery mode screen appears. Now move across to your PC, and select the “Restore” button in iTunes.