Most of the time, your iPhone gets stuck on a spinning wheel because something went wrong during the reboot process. This can happen after you turn on your iPhone, update its software, reset it from Settings, or restore it to factory defaults.
What do I do if my iPhone is stuck on the spinning wheel?
Press and hold the volume down and side Sleep/Wake buttons at the same time. When the Apple logo appears on screen, release both buttons.
Why does my iPhone keep showing a loading screen?
If your iPhone force-restarts but continues to display the black screen with a loading circle, you’re likely dealing with corrupt system software. To fix that, you must reinstall or reset iOS in Recovery Mode.