How to reset the Xiaomi Robot Vacuum S20?

Reset the system: 
Press and hold the Recharge button for 5 seconds until you hear a "beep", and then press and hold the Recharge button for 5 seconds again until you hear the voice prompt. The robot vacuum then restarts, and settings like scheduled cleaning and Wi-Fi are restored to factory defaults.
Reset the Wi-Fi: 
When the robot vacuum is turned on, press and hold the Power button and the Recharge button for 7 seconds. The Wi-Fi is successfully reset when you hear a voice prompt.