Well, wasn’t I surprised to discover that you can’t restart the iPhone 8 in the same manner as the iPhone 7 (pressing power & down volume buttons). I tried doing that when the Skype app kept crashing after setup and discovered that the phone emits siren-like noise. I have yet to set up my iPhone 8 “as new”. Anyway, the noise scared the crap outta me.......Anyway, to reboot the iPhone 8, quickly press the Up volume button and then quickly press the Down volume button and then press and hold on the Power button until you see the logo. By the way, you do not have to hold all three buttons simultaneously. Anyway, I hope this information is helpful to you. Take care.