Need to send your Samsung Galaxy S II back in for warranty reasons or maybe you just want to start over with a stock device. Here’s the quickest way to unroot the device and get it back to fully stock.
I. Before You Begin.
1. This will erase everything off of the device. So back up any pictures, contacts, etc. you don’t want to lose.
2. THIS ONLY WORKS ON THE T-MOBILE VERSION OF THE GALAXY S II. For any other version please head to our Galaxy S II How To’s and look for your specific device’s unrooting procedure instead.
II. Unroot the Samsung Galaxy S II
1. Download the stock firmware and save it to your computer.
2. Plug in your device via USB cable and mount the sd card so you can transfer files to it.
3. Copy the original firmware .zip file to the root of your sd card (Not in any folders, just on the sd card itself. Don’t unzip the file either).
4. Unplug the device.
5. Turn off the device.
6. Turn the device back on by holding down Volume Up, Volume Down, and Power at the same time until the recovery screen comes back on.
7. In the recovery menu, select Wipe Data / Factory Reset
8. Now, select Flash .zip from SD card and select the .zip file we just put on the sd card.
9. Once it flashes, select reboot system now and wait for the device to reboot.
10. All set!