Battery Drains Very Quickly.
So, I have a Samsung Galaxy Tab 2 7.0 P3110, but for the past month I have been experiencing battery drains very quickly. For instance, I would charge the tablet to 100%, but when i take out the charger I would experience a large loss of batter such as in 2 minutes I would lose about 20 % of the battery. So I wanted to replace my battery so I went to the Samsung Store in Westfield, where I went to the 'Smart Team' who I would thought replace the battery for me, but however they decided that they thought it was a firmware problem which I knew it wasn't, they took it to recovery mode where i had a custom recovery so they used that as an excuse, how that is the reason i'm experiencing this. I really wanted to go hell on that guy, since I had been rooted for over a year I was still on an official firmware. So I want to unroot this tablet and just go back to how it genuinely came out, i can't find a guide or somehow if someone can, just post it here please.