Odin3 is a PC application that was designed to help us update Samsung Android phone firmware. You can install stock firmware and kernel with Odin3. You can also use it to root Samsung Galaxy S II too. Therefore, you are able to flash CF-Root into Samsung Galaxy S2. It is a must have tool if you like to try custom firmware. And get more juice out of your Samsung Android phone.
Note – Do ensure Samsung Kies is not opened or loaded in system tray when using Odin3.
Download Odin3 v1.85 here.