1. Turn it off.

2. Hold down the volume down key and the on key for a long time until an exclamation point and a small green robot appear in the interface.

3. Press the power on/off key briefly, press the volume key to select "Erase data/restore factory settings" (OK), and press the volume key to select "Yes-delete all user data", and the system will automatically restore factory settings. Press OK and jump to "Restart the system now". Press the power-on key briefly and the system will start automatically.

But it is best to back it up before recovery, otherwise the internal information will disappear.