How to restore the system before upgrading Xiaomi Robot Vacuum S10T ?

Take out the dustbin or two- in-one Water tank from the main unit, erect the main unit, and perform the following operations:
restore the system, turn over the main unit, use a needle to press and hold the reset button for 10 seconds, hear the voice prompt, the main unit will automatically restart, the Pre-set cleaning and WiFi and other related settings will be restored to the factory state, and the system will be restored to the previous firmware Version.