How to Root Samsung Galaxy S2 Official 4.1.2 Jelly Bean!

Now that you know how to update the Galaxy SII let's see how to root them.After rooting, you'll be able to install such apps which require root access.

Disclaimer:
In order to root your Android device, we will require to flash a rooting kernel to your phone. We will be flashing a rooting kernel in your Galaxy S2 I9100 running on XWLS8 Android 4.1.2 Jelly Bean official firmware using ODIN. This will root your device. However, in this process you may lose your personal data and settings.
Please do note that once your device is rooted, you warranty will be void; However, you can reclaim the warranty by re-applying official firmware update.

If you agree with the above lets get down to business:

1. Extract Odin zip file and you will get Odin3 v3.07.exe or Open it if you already have it or download it here
2. Download the root file here.   
3. Extract the downloaded file and you will get Siyah-s2-v6.0b4.tar.
4. Power off your phone. Wait 5-6 seconds to confirm complete switch off.
5. Now, put the Galaxy S2 I9100 phone in Download Mode by pressing pressing and holding down the Volume Down and Home buttons while pressing the Power button. A screen will come up; press Volume Down key to continue to enter Download Mode.
6. Now run Odin3 v3.07.exe (see Step 2) as an Administrator because Admin privileges is required to complete the process smoothly.
7. Now connect your Galaxy S2 I9100 with your PC using USB cable. A message will appear under Odin’s message box in the bottom left saying “Added!!”. If you don’t get it or you have missing driver download it here.Then try another USB port. If that too doesn’t work, then reinstall the USB driver if u don't have it get. If you successfully see the “Added!!” message in Odin, you are good to go. Also, check for COM port with a number in Yellow to make sure that you have successfully added your device. 
8. Select these files in Odin at respective button:
• Click the PDA Button, and select the Siyah-s2-v6.0b4.tar file.
• In Odin window, make sure Auto Reboot and F. Reset Time checkboxes are selected.
• Double check everything. Hit the START button to begin the flashing process.
• Once the flashing process is completed, the tablet will reboot automatically and you will see a PASS message in the top-left-most box. You can now unplug the USB cable to disconnect your device from computer.

Your Galaxy S2 I9100 running XWLS8 Android 4.1.2 Jelly Bean firmware is now rooted.

Here is another way to root your device if you do not want to use ODIN:

• Download Root package for XWLS8 or XXLS8 jellybean firmware from here.
• After downloading the file, copy the file onto external SD card on your phone.
• Now turn off phone and start in recovery mode. To start phone in recovery mode, hold volume up+home+power buttons together for few seconds until Samsung logo appears.
• Now use volume up/down key to select Install update from External storage and press power button to choose this option.
• Now, select the root zip package you downloaded in step 1. It should be: PhilZ-cwm6-XXLS8-FOP-4.00-b22-signed.zip
• Done, within few seconds, phone will be successfully rooted. Reboot now. 

If there are any issues, feel free to post in the comments section