Hi i have the same Problem, if i select System Update the settings close and i arrive at the home screen.
I tried booting into recovery with volume up + power. This gives me a new screen where i should select boot mode (recovery, fast, normal) with Volume down/up but i can not select anything.
If i press volume down + power it shows a different screen that has blue chinese lines and the top one is yellow.
How can I update to original xiaomi rom?