For those of you on custom ROMs and you don’t want to unroot back to Gingerbread to take the official T-Mobile ICS update, here’s how to easily unroot/unbrick your Galaxy S2 SGH-T989 back to official ICS.
*Note – This method requires a Windows computer. Sorry Heimdall does not support T-Mobile Galaxy S2 yet.
Step 1. Connect a microUSB cable from your T-Mobile Galaxy S2 SGH-T989 to your computer. Then hold down Volume Up, Volume Down, and Power button together for about 10 seconds.
Step 2. When your phone resets, you will feel a small vibration, let go of the Power button but hold the rest of the buttons down.
Step 3. When you see the warning screen, hit Volume Up button to enter ODIN download mode.
Step 4. You should see Downloading… sign like below.
Step 5. Download the file SGH-T989_UVLE1_ICS.zip and unzip, you should find 3 files.
Run the odin3 v1.85.exe file by double-clicking on it.
Step 6. Choose “PDA” and choose the file T989UVLE1_T989TMBLE1_T989UVLE1_HOME.tar.md5 and hit the “Start” button.
DO NOT MESS WITH ANYTHING ELSE!!! K.I.S.S. KEEP IT SIMPLE STUPID!!!
Step 7. Your phone will start installing/unrooting to the new T-Mobile official ICS update.
Step 8. After about 10-20 minutes, you phone will reboot once unrooting is complete.
Step 9. If your phone boots up and you have no force closes or any weird errors, you are done. BUT, if you do have some errors, you will need to do a factory reset in stock recovery.
Make sure your microUSB cable is NOT PLUGGED IN, then hold down Volume Up, Volume Down, and Power buttons together.
Step 10. When your phone resets, let go of the Power button.
Step 11. Once in stock recovery, choose “Wipe data/factory reset” and hit the Power button.
Step 12. Choose “Yes”.
Step 13. Reboot and you should find a factory fresh stock ICS on your T-Mobile Galaxy S2 SGH-T989.