Hi Optic. I searched for a guide but I couldn't find one I liked so I put this one together for you.
This is for the T-Mobile Galaxy S2 SGH-T989 phone ONLY.
This will void your warranty. Proceed at your own risk.
That said, this is pretty simple, but read through it carefully before you begin.
Make sure on your phone USB Debugging is checked in Settings > Developer Options
Make sure your phone is charged. After you plug in the USB cable in step 2, put your phone down and don't touch it. Losing power or a loose USB cable during installation could cause a
big headache.
Download and install Kies. You don't need to use Kies for rooting but it comes with the latest drivers. You may also need it for future updates from T-Mobile. After its installed, plug in your phone to the computer and let Kies find it to make sure the drivers are installed. After that you can close out Kies. You won't need it anymore.
Make a folder on your PC to put these files.
Odin 1.85 - Make a sub folder and extract Odin in it.
ClockworkMod Recovery
Superuser - put this on the root of your sd card. Meaning not in a folder.
1 - Launch Odin by double clicking the Odin3 v1.85 file. Plug your USB cable to your computer but
not your phone.
2 - Power off your phone. Then hold down
both volume buttons and plug the USB cable into your phone. Press the
volume up button when you see this menu.
You will then go to the download screen.
3 - Wait for the Com port in Odin to turn yellow as in the pic. You do not need to check anything that isn't already. Just be sure that Re-Partition is
NOT checked. It shouldn't be.
4 - Select
PDA in Odin and browse to the
ClockworkMod file you downloaded. Select it. Now press
Start and Odin will flash the recovery. When it is finished you will see a green
PASS in the top section.
5 - Odin will reboot your phone and you can unplug it. You should now have ClockworkMod Recovery 5.0.2.6 on your phone.
Now you want to go to your new recovery.
Power off your phone. Hold
both volume buttons and the
power button at the same time. When the phone vibrates, let go of the power button but
keep holding both volume buttons. In a few seconds you should be in the recovery menu. Use volume buttons to move up/down and power button to select. *if power button doesn't work, use your home button (2nd from left on bottom of phone)*.
Go to
install zip from SD Card. Then go to
choose zip from SD Card. Select the
Superuser.zip file. On the next screen select yes. Superuser will install. You may get an error and installation aborted message. Just try again. It may take several times.
Reboot your phone and check to see if you have the Superuser app in your app drawer. Congratulations! You are now rooted.
Just to be sure, download an app that requires root, Like Titanium Backup, and make sure it works.
Before you do a lot, go back to CWM recovery. In backup and restore, select backup and it will make a nandroid backup. If you have problems in the future you can restore it. Make sure you have at least 1gb free on your sd card. That's about the size of a nandroid.