Battery drain problem of BB has been well documented and I have tried most of them and still no improvement and decided to do one last throw of the dice.
History: I have been using 8520 with OS 4.6 with no problem for years and all of a sudden, one day, it began to drain battery horribly. (Gone in 10 minutes)
When new batteries made no difference, I upgraded OS to 5.0.0. and it made a marked improvement. Now, it lasts 3 hours (which is useless as a mobile phone).
This is not a hardware problem (if so, why the OS upgrade made any difference?) and battery is new. So it is an OS problem (am I correct?)
I have tried taking the battery off and reboot and I checked that only basic 5 app are running. I even re-installed the newly downloaded 5.0.0 but made zero
Could anyone tell me what is happening? Any constructive suggestion much appreciated.
Thank you very much.