In soft reset - Press power button by holding the power button down for 15 min until you see the logo.
In hard reset - 1. Unplug the device
2. Power off the device by holding power button.
3. Wait 5 seconds, then hold down both the volume up and power buttons.
4. Press the volume up button to move the arrow until it is pointing at the Recovery Mode option, then press the volume down button to select it.
5. The logo should appear for a few seconds, then you should be in the system recovery menu. Use the volume up / down buttons to highlight the factory reset option, then press the power button to select it.
6. Use the volume up / down buttons to highlight the “Yes — delete all user data” option, then press the power button to select it.
7. Once you completed, you should be returned to the system recovery menu. Select reboot system now, then press the power button to select it.