Why does my phone battery draining fast and the camera is not working for Lumia 535?

[Windows Central Question]

hi, i have tried upgrading my lumia535 to windows 10 preview but then ive downgraded them back to windows 8.1. the problem is that my battery drains very fast although the charging takes a long time. and now my camera is not working as well. the phone is 1 year old. i believe that the problem is caused because i downgraded to windows 8.1 denim. can you help to explain the procedure to change it to lumia cyan? thank you very much!

 

[Adarsh Shiragannavar]

Use the Windows Phone recovery tool.

 

[inalex]

I have the same problem though it's after I upgraded to wp10 on my l535. Battery drain is fast although camera is working now. But the battery drain is worrisome. What can I do?