Redmi 4A account problem
 

Hi!
I have redmi 4a with mi account. I downgrade to miui8 version and made account remove in edl mode and reset account lock. After that made factory reset. All is ok, phone is working, i can connect to the wifi , i can update many application, phone doesnt locked back. But if i upgrade to miui9 version , than phone relocked. How can i solve this problem?