Step 1: Head on over to the Samsung Apps website and download the official and latest version of the Kies application.
Step 2: Find the downloaded Kies application on your machine and install according to the included instructions.
Step 3: Odin is the software which allows Ice Cream Sandwich to be flashed to the device. Odin is required for this process and can be downloaded here.
Step 4: Enable ‘USB Debugging‘. You can do this by going to ‘Settings >> Applications >> Development‘ and checking the relevant little box.
Step 5: Download the Android 4.0.3 firmware file from this link.
Step 6: Open up the ‘Odin‘ application and click the big button which is labeled ‘PDA‘ (located under the heading ‘Files [Download]). Navigate to the extracted folder containing the downloaded Ice Cream Sandwich files and locate the file which is appended with the ‘.md5′ extension.
Step 7: After making sure the handset is totally turned off, turn it back on by pressing the ‘power‘, ‘volume down‘ and ‘home‘ buttons together. A warning sign will appear on the screen, giving you the opportunity to back out now if you so desire. If you decide to proceed, press the ‘volume up‘ button to dismiss the warning and activate the device’s download mode.
Step 8: Connect the Galaxy S II to the computer via the USB cable, skipping back to the Odin application that is running and wait for it to detect the connected device. If nothing happens, make sure you followed step 2 correctly and installed the required Kies application.
Step 9: Underneath the ‘Control Panel‘ heading in Odin lies a big button which says ‘Start‘. If you still have the courage, and everything has gone to plan so far then press it and give your Galaxy S II the treatment is so sorely deserves.
