Update Galaxy S2 I9100G to Android 4.1.2 Jelly Bean with AOKP Build 5 ROM [How to Install]
Update Galaxy S2 I9100G. Photo: XDA Developers

The younger sibling of Galaxy S2, the Galaxy S2 I9100G, finally gets the latest Jelly Bean update - Android 4.1.2 - with the release of AOKP build 5 ROM, alongside a host of other Samsung devices including Galaxy S2 I9100, S3 I9300, Nexus 7, Galaxy Nexus I9250 and Nexus S I9020. The favourite custom ROM for Android devices brings the latest Jelly Bean features on its newest build.

AOKP Build 5 Based Android 4.1.2 Jelly Bean Features

  • Custom NavBar for Tablets
  • NavBar widgets are borrowed from Ice Cream Sandwich (ICS)
  • Highly customisable Lockscreen Ring targets, with a shiny new editor in ROMControl (also thanks to CM for the base of the framework part)
  • Alternate default app picker (like in GB)
  • Menu UI Overflow Toggle
  • Option to disable vibration for Notification expansion
  • RAM Bar in the Recents panel
  • Timeout and instant lock options for Slide lock
  • Tons of beautiful new icons by Kwes
  • VPN Traffic statistics in human readable format

Key Points to Note

  • The AOKP ROM and the instructions given in this guide are compatible only with the Galaxy S2 I9100G model and will not work on any other device. Verify your device's model number by navigating to Settings > About Phone.
  • Do a Dalvik Cache wipe before continuing from the recovery mode.
  • Samsung KIES will not recognise your phone after installing the AOKP build 5 based Android 4.1.2 Jelly Bean update, as it is a custom ROM release.
  • IBTimes UK advises users to back up apps, important data and settings to avoid data loss while installing the Android 4.1.2 Jelly Bean update on your Galaxy S2.
  • The instructions provided in this guide are meant for reference purpose only and do not cover any warranty claims involving device damage or issues arising out of using the AOKP Build 5 firmware update. Users are cautioned to proceed at their own risk.


  • Ensure that you have installed the correct USB drivers for your Samsung Galaxy S2 to enable connectivity with the computer. Download Samsung Galaxy S2 USB drivers.
  • Enable USB debugging mode by navigating to Settings > Application > Development. This feature helps in connecting your Android phone with the computer.
  • Verify that your phone's battery is at least 85 percent charged to prevent unexpected device shutdown while flashing the AOKP custom ROM or installing the Android 4.1.2 Jelly Bean update.
  • Ensure that your Samsung Galaxy S2 phone is factory unlocked. Also, verify that the device is rooted and ClockworkMod (CWM) Recovery installed on it.

How to Install AOKP Build 5 Based Android 4.1.2 Jelly Bean Update on Galaxy S2 I9100G

Step 1 - Download Android 4.1.2 AOKP Build 5 Jelly Bean ROM and Google Apps for Galaxy S2 I9100G on your computer.

Step 2 - Connect and mount your Galaxy S2 USB mass storage on your computer using an USB cable.

Step 3 - Copy the downloaded Android 4.1.2 ROM ZIP and Google Apps zip files to the root folder on your phone' s SD card.

Step 4 - Power off your phone and unplug the USB cable from the computer.

Step 5 - Press and hold the Volume Up, Menu and Power buttons together to power on the phone and boot into Recovery Mode.

Step 6 - In CWM recovery, do a full data wipe first. Then navigate to flash zip from SD card option and tap the Power button to select it.

Step 7 - Hit the Power button once again and click choose zip from SD card.

Step 8 - Use the volume keys to navigate to the Android 4.1.2 ZIP file that you copied to your phone's SD card, and select it using the Power button. Double-tap on the ROM zip file to begin the installation. Then, confirm the installation on next screen and the installation procedure should begin.

NOTE: Repeat this step again for installing Google Apps.

Step 9 - Once the ROM is installed, hit Go Back and tap Reboot System Now from the recovery menu. The phone will restart now and the first boot may take about 5 minutes to complete. So, leave it alone.

AOKP Build 5 ROM based Android 4.1.2 Jelly Bean update is now successfully installed on your Galaxy S2 I9100G. Go to Settings > About Phone to verify the firmware version installed.

[Source: Team Android]