Redmi 2014818 says "unfortunately com.android.systemui has stopped" I have Xiaomi HM2 LTE IN. Also called Redmi 2014818. Every time I try to open any MI app the phone says "unfortunately process com.android.systemui has stopped".  

Then when I tap "view summary" the lock screen appears.  

So it has made using the phone difficult. 

Luckily this error message doesn't appear when I open any non MI app like WhatsApp, Chrome.
Solved it myself. 
1. Downloaded update. 
2. Renamed it update.zip. 
3. Pasted it in sd card "in" the phone from another "in" the phone folder using RAR app. 
4. Used power and volume button etc (in followed recovery instructions). 
6. Did it. Much relieved .