Galaxy S2
CM10.1 official custom ROM with Android 4.2.1 update released for Galaxy S2. Samsung

Followed by the release of CyanogenMod 10.1 (CM10.1) unofficial builds for Samsung's second generation Galaxy S series smartphone with model number I9100, the CyanogenMod team has now released the official CM10.1 nightly for the device. The official Jelly Bean custom ROM brings Android 4.2.1 update for Galaxy S2 which is currently running on Android Ice Cream Sandwich software. Almost all the features are said to be working properly, but the build carries a few bugs.

Samsung is expected to roll out Jelly Bean upgrade for Galaxy S2 sometime this year. Galaxy S2 users, who cannot wait for the official release and wish to experience the features from the latest version of Jelly Bean by installing the CM10.1 custom ROM, may follow the guide below. IBTimes UK reminds its readers that it will not be held liable for any damage to the device. Users are advised to verify the model number of the devices before proceeding since the CM10.1 nightly works only on the Samsung Galaxy S2 I9100 not on any other variant. Flashing incorrect ROM may brick the device.


1) Download and install USB Drivers for Samsung Galaxy S2 in your computer.

2) Enable USB debugging mode;

[a) Navigate to Settings

b) Scroll down and tap on Developers options

c) Check 'USB Debugging' from there]

3) Ensure the device is rooted and ClockworkMod (CWM) recovery is installed.

4) Perform a Dalvik Cache wipe before proceeding from the recovery mode.

5) Create back-up for all your important data.

6) Ensure the battery of the device carries more than 80 per cent of charge.

Steps to install CM10.1 Android 4.2.1 Jelly Bean official custom ROM on Galaxy S2 I9100

1) Download CM10.1 Android 4.2.1 Jelly Bean nightly for Galaxy S2 I9100 to you computer [Alternative link]

2) Download Google Apps package

3) Connect the phone to the computer using USB cable and copy both the downloaded zip files to the SD card of your device

4) Disconnect the USB cable from the phone and switch it off

5) Enter into Recovery mode by switching on the phone while pressing and holding Volume Up, Menu and Power buttons together

6) In CWM recovery, perform data wiping task. Once the action is completed, return to the recovery menu

7) Scroll down to 'Flash zip from SD card' and select it using the Power button, then select 'Choose zip from SD card' by pressing Power button again. Now navigate to the Jelly Bean custom ROM which you have copied to the SD card, select it using Power button and confirm installation on the next screen

8) After the ROM is installed, repeat the same procedure to install Google Apps package

9) Once the installation process is completed, return to the main recovery menu and select 'Reboot System now.' The phone will take about five minutes to boot the first time

Your Samsung Galaxy S2 I9100 is now updated with CM10.1 official Jelly Bean nightly featuring Android 4.2.1. Navigate to Settings>> About Phone to verify the software running on your device.

[Source: Team Android]