Rebooting an iPhone 7 or iPhone 7 Plus requires squeezing and holding both the Sleep/Wake and Volume Down buttons for less than 10 seconds, until the point when the Apple logo shows up, restarting an iPhone 8 or iPhone 8 Plus takes three easy steps.
- Press and rapidly discharge the Volume Up
- Press and rapidly discharge the Volume Down
- Press and hold the Side button (known as power) until the point when you see the Apple logo.
Powering off regularly still requires holding down the Side button for a few seconds until the “slide to power off” prompt appears. In iOS 11, there’s also a “Shut Down” option in the Settings app at the bottom of the General menu.
Force restarting an iPhone is different than recovery using DFU (Device Firmware Update) mode, for which the steps remain the same as the iPhone 7 and iPhone 7 Plus.