Step 4. Run ODIN3v1.85.exe by double-clicking on it. If you don’t see a yellow highlighted box with a random COM number, download and install Samsung USB Drivers.
Next, DON’T TOUCH ANYTHING ELSE but hit the “PDA” button.
Step 5. Choose the Jeboo kernel .tar file you downloaded earlier.
Step 6. Hit the “Start” button and this will start flashing the kernel. Once it says “PASS!” your Galaxy S2 GT-i9100 should reboot.
Step 7. Once rebooted, download Superuser zip file straight to your phone or you can also copy it over from your computer.
Step 8. Turn your phone again then hold down Volume Up, Center Home, and Power buttons together for about 20 seconds until your phone reboots into CWM Recovery.
Step 9. Choose “Install Zip”.
Step 10. Choose “Choose zip from Internal sdcard” or “Choose zip from sdcard”. (Depending on where the Superuser zip file is)