This is the problem with the GDR2.. battery issues with my L1520 also..... Hardly 4-5hours of backup. You need to re-install the software using Lumia recovery tool.... Hope that makes your phone work fine
Re: My phone's (Lumia 930) battery draining very quickly 10 to 15 days ago i have noticed that .....
Same problem is faced by me.. With Lumia 1520.... Yet there is no solution