Error Updating Mi2s

Jan 14, 2016
I have a mi2s with MIUI 7 version 5.11.12
Android version is 5.0.2 LRX22G
THE memory IS so divided 3.7 GB of internal mem and 25.6 of internal storage.
I receive notifications of updates shown by " update" that drain readily and at installation time rose to 90 % and then goes into error .
I read that I should download a previous update ( 5/11/20 ) to unify the memory after which resume with updates without problems , but I did it for this update I rose to 90 % after that crash .
Does anyone know tell me exactly what to do to overcome this problem ?

Thank you