1. Press and hold down the volume increase button, HOME button and power button at the same time when turning off the machine, and release it after the screen lights up to enter recovery mode.
2. After entering the recovery mode, the English selection interface will appear. Select WipeData/FactoryReset to confirm-then select the middle line YS-delete; ; Of course.
3. Select WipeCachePartition and confirm again.
4. Finally, select the first item rebootsystemnow to restart the phone. Note: When doing the above operations, be sure to back up important data such as personal data, phone book and SMS, because these data will be cleared when unlocking.