WARNING: by rooting your phone or installing custom ROMs, you may be voiding your warranty. I take no responsibility if your phone is damaged or bricked by following these instructions. Always backup your phone before altering its software in any way this also includes your data.
I suggest reading instructions from multiple sources to ensure you have at least a vague idea of what you are doing.
Download and install Samsung Kies 2.6 is the current version, version 3 is only for newer phones, this will ensure you have the latest Samsung USB drivers and a tool for backing up your data.
Firstly your phone will need to be rooted to be able to flash it with a new ROM. I chose Cyanogen because they seem to have one of the cleaner, leaner installs for the Samsung Galaxy i9100.
You will need to download and have available on your phones SD card the following software. I’ve bundled the software into a zip. The folder ODin v3.07 goes on your PC and the stuff in the folder \ToPhoneSD goes either on your internal SD or external, just make sure you know where it is.
SamsungGalaxyKitKat.zip (250MB)
I chose the Pico version of GApps because I was having memory issues, “insufficient storage space available in system partition”, with the larger versions of GApps including mini. These larger versions include more Google Apps. The pico version, I think only has the Google Services and Google Play, the rest you can install once your phone has been flashed.
Odin – I used v3.07 but it looks like anything newer will also work
CWM-KitKatCompatible-i9100.tar – CWM Recovery 6.0.4.5
Cyanogen Snapshot ROM – I used the 2014-10-08 snapshot
Pico GApps – MediaFire: http://goo.gl/WPCGJz
Or you can choose your own GApps from xda
SuperSu Download: http://bit.ly/1l8SEUz
Triangle Away app: http://bit.ly/1fb5ccD
Rooting Samsung Galaxy S2 i9100
- Turn off your phone. Now, press and hold down the Volume Down, Center Home, and Power simultaneously. Continue holding until you see a warning screen (about 3 seconds).
- Hit Volume Up. Then, connect your Galaxy S2 to your computer.
- Double click Odin3 v3.07.exe. This will run the program. You should then see a yellow highlighted box with COM and a number in it.
- Hit the “PDA” button. This should be in the checklist below the start button.
- Browse to the CWM-KitKatCompatible-i9100.tar file in the Odin 3.07 folder.
- Hit “Start.” The kernel should start flashing. Your Galaxy S2 will restart and you see the word “PASS!”. You’ve now installed CWM Recovery v6.0.4.5 which will allow you to flash to KitKat.
- Turn off your phone. Then press and hold Volume Up, Center Home, and Power until your phone goes into CWM Recovery (about 20 seconds).
- Choose “Install Zip.” It should be the second option on the list.
- Click “Choose zip from External sdcard.“
- Find the Superuser file. CWM-SuperSU-v0.99.zip. This will install su binary and Superuser to your galaxy S2.
- Confirm by clicking “Yes” when prompted.
- Reboot. You’ll find an app called SuperSU. The first time you use it, you’ll have to grant permission via a popup window. Then, you’ll be good to go. Enjoy your newly rooted phone!
Flashing Samsung Galaxy S2 i9100
You have to have a rooted phone before you can follow these instructions.
- Turn off your phone. Now, press and hold down the Volume Up, Center Home, and Power simultaneously. Continue holding until you see a warning screen (about 20 seconds).
- Choose “Install Zip.” It should be the second option on the list.
- Click “Choose zip from External sdcard.“
- Find the Cyanogen ROM. cm-11-20141008-SNAPSHOT-M11-i9100.zip
- Confirm by clicking “Yes” when prompted.
- Do the same to install the pa_gapps-modular-pico-4.4.4-20141011-PS34-signed.zip
- Now the SuperSU file UPDATE-SuperSU-v2.13.zip
- Wipe Data/Factory Reset
- Wipe Cache Partition
- and finally under Advanced – Wipe Dalvik Cache
- Done, Reboot System Now