Samsung Galaxy S2 GT-I9100 has been made surprisingly compatible with Android 4.4.2 KitKat version using a custom ROM named SlimSaber. It features compiled custom tool chain Sabermod for more battery life and optimised performance.

SlimSaber Custom ROM

SlimSaber KitKat custom ROM runs Android 4.4.2 version and based on Android Open Source Project compatible with Galaxy S2 I9100. It features the following changes for the previous flagship smartphone:

- Optimised performance and improved battery life due to Sabermod custom tool chain.

- Compiled with the most GCC optimisation level.

- Additional ARMv7 and Cortex A9 optimisations.

- Smoother system running and responsive.

- Better memory management.

- More AOSP fixes and improvements.

Requirements

1. Use the Samsung Galaxy S2 GT-I9100 smartphone only.

2. Root the smartphone and install a custom recovery such as ClockworkMod recovery.

3. Create a manual backup of all personal information, settings and data files stored on your Galaxy S2.

4. Make sure that the battery level is at least 50 per cent.

5. Enabled USB debugging mode by going to Settings > Applications > Development > USB debugging.

6. Download and install USB drivers on your computer for Galaxy S2.

7. Download the SlimSaber Android 4.4.2 ROM and Google Apps package to your computer.

Warning: SlimSaber requires manual installation on your Galaxy S2 which may damage the smartphone. IBTimes and SlimSaber developers are not responsible for any errors that may occur on the device. Read, understand and follow the instructions to prevent damaging your Galaxy S2. Do this at your own risk.

Flashing Instructions

1. Connect the Samsung Galaxy S2 GT-I9100 to your computer using a USB cable.

2. Copy and paste the SlimSaber Android 4.4.2 custom ROM and Google Apps package you've downloaded earlier to the SD card of your smartphone. Don't extract the zip files.

3. Disconnect the Galaxy S2 then turn it off.

4. Reboot into recovery mode by pressing and holding "volume up + home + power" keys at the same time till the Samsung logo appears.

5. Inside the recovery mode, create an Android backup of the current ROM by selecting "backup and restore > backup." It will be saved inside the SD card which you can restore anytime.

6. Perform a complete wipe on your device. Select "wipe data/factory reset" and "wipe cache partition" then "advanced > wipe Dalvik cache."

7. Install the SlimSaber Android 4.4.2 KitKat ROM by selecting "install zip from SD card > choose from SD card > look for the custom ROM > confirm installation." Apply the same with Google Apps package.

8. After the installation, go back to the main menu then select "reboot system now."

9. It may take up to five minutes till the device reaches the home screen due to first time running the ROM.

Congratulations! Your Samsung Galaxy S2 GT-I9100 is running the latest Android 4.4.2 KitKat version.

For comments or questions, send your feedback to XDA developer original thread or Team Android main page.