The technique to induce restart or an iPhone 8 or iPhone 8 Plus was altered by apple at 2017.
While restarting an iPhone 7 or iPhone 7 Plus requires pressing and holding either the Sleep/Wake and Volume Down buttons for a minimum of 10 seconds before the Apple logo appears, restarting an iPhone 8 or iPhone 8 Plus is a 3 step procedure which requires the Volume Up button, the Volume Down button, along with also the Negative button on the apparatus.
How to Force Restart iPhone 8
To begin with, you have to quickly press the Volume Up button. Then, quickly press again the Volume Down button. In the end, press and keep holding the Side button (aka electricity) till you will see the Apple logo on the screen.
Powering off frequently still needs holding down the Negative button for several seconds before the “slide to power off” warning appears. In iOS 11, there is a Shut Down option also.
Apple made this change due to iPhone 8 along with iPhone 8 plus, pressing and pressing the Negative aka Sleep/Wake button and among the Volume buttons today triggers the Emergency SOS attribute.