Device freezes during startup?

Connect the device to iTunes on your Mac, then force it to restart: On an iPhone 6S or earlier or an iPad, press Home and Sleep/Wake; on a 7 or 7 Plus, press Volume Down and Sleep/Wake; or on 8, 8 Plus or X, press and release Volume Up, then press and release Volume Down, and hold the Side button until you see the recovery mode screen; when iTunes asks, choose Update. When that’s done, restore your backup.