How to root Samsung Galaxy s2 (i9100)

1. Check your ROM version
2. Download the appropriate CF-Root for your ROM
3. “Flash” the kernel with Odin

There are a couple of different options but I’ll only explain one. Before you start. There is a possibility of loosing the guaranty on you phone, and also, if you break anything it’s not my fault. This is only an explanation of how I did it.

What you need. Your phone, a windows PC and a usb cable to your phone.

1. Check the version of your ROM (Firmware version)
On you phone go to menu->settings->about phone, scroll to the bottom. You will notice that your ROM has a long name that looks something like this x.x.x-xxxXWKF3-xxxxxx. The last 5 digits in the “middle” part of the name shows the name of your ROM.

2. Dowload the appropriate CF-Rooted kernel for your ROM
Now that you know the version of your ROM, you can go to the next step. A developer called Chainfire has been kind enough to set up prerooted kernels with all the tools you need to get the best use of your rooted phone

Check the following link,¬†CF-Root¬†press ctrl+f (cmd+f if you’re on a mac) and search for the last 3 digits in the name of your ROM which in this case will be KF3. Double check the name to see if it’s correct and then download the kernel

3. “Flash” the kernel with Odin3 v 1.83
Download Odin, you can find it with an easy google search.
Extract the file and open the program.

Power off your phone and power it on by holding the following 3 buttons simultaneously.
Volume-Down + Home (middle button) + Powerbutton. If you did it right you should find your self on a screen with the title ODIN MODE and the option of restarting or continue. Press Volume-Up to continue.
Now connect the USB-Cable to your phone. Windows should now try to install the drivers for you phone, just let it finnish. If the driver install fails you should check Samsungs support pages for the drivers to your phone. If it works, Odin should look like this:

Now click the PDA button and point it to the CF-Rooted kernel you downloaded. Make sure Repartition and Phone Bootloader are not checked (if you don’t know what your are doing). Now click Start and wait until you see this screen

Your phone should restart by itself. When it’s up and running again, check your applications menu and see if you have a new app called CWM. If you do, you are good to goo. Happy rooting!