One: Data backup must be done before upgrading
The common backup method is the iCloud backup method that comes with the mobile phone. However, due to the troublesome recovery, we can also use powerful apple recovery wizards and other third-party software. Be sure to back up your data before upgrading. Remember to remember! ! ! ! If there is no backup then the white apple appears to be restored using the above software.
After doing the above preparations, you can enter the formal recovery tutorial.
II: How to do if you upgrade iOS12?
Press the power button to wake the screen after the screen is locked
1> Press the power button to lock the screen;
2> wake up the device again via the power button / Home key;
3> repeat the lock screen wake-up operation 5 to 10 times or more.
Factory reset/Force restart
1> Hold down the Home button and the power button at the same time;
2> Press for more than 10s until the apple's logo appears on the phone screen;
3> After restarting the phone, go to Settings - General - This machine checks to see if your phone version has been upgraded to iOS 12. If not, please upgrade again.
Restore your phone via iTunes (make sure your phone has been backed up and then do the following.)
1> Connect the phone to the computer via the USB cable, wait for iTunes to recognize the phone information, and click to enter the device to view related information;
2> Click the "Summary" option and select "Restore Device";
3> Select the firmware you want to restore, then click "Restore";
4> Then restart the iOS12 upgrade again.
5> If none of the above methods work, download the latest iOS12 firmware on your computer and then use iTunes to update the firmware. At present, the success rate of iOS 12 upgrade through iTunes is above 98%, so everyone can upgrade through iTunes.