Upgrade Galaxy S2 I9100 to Android 4.1.2 with Vanilla RootBox Custom ROM [Jelly Bean]

Recently Google rolled out Android 4.1.2 Jelly Bean update for Nexus 7. The update has a build number ‘JZO54K’ & comes with improved performance and stability fixes. No sooner did Google release the update, XDA Recognized Contributor bajee11 ported it to Samsung Galaxy S2 in the form custom ROM called Vanilla RootBox.

This ROM is compiled by mixing two famous custom ROMs called AOKP & Cyanogenmod. They are the best ROMs at their places when customization has to be done on your phone. Vanilla RootBox ROM also includes OTA update app which can let you upgrade it without downloading the whole ROM again.

Lets move on further to learn how one can update his/her Galaxy S2 GT-i9100 with Android 4.1.2 Jelly Bean based custom ROM Vanilla RootBox.

Disclaimer: The Procedure described in this article are risky & can cause damage to your device. You should not try to attempt this if you are unaware of these things. Please follow this guide completely at your own risk. If any damage happened to your device while following this tutorial, neither we nor developer should be held responsible for it.

This guide is intended only for Samsung Galaxy S2 GT-i9100 (International variant). Trying this on US variants of Galaxy S2 or on any other device can cause damage to your phone.


  • For uninterrupted installation of the ROM, charge your phone at least up to 70% battery level.
  • It is recommended to take a backup of all important data like SMS/MMS, APN, contacts etc. since it can be restored back if anything goes wrong during the installation.
  • In order to use USB debugging mode on your phone, device specific drivers must be installed on your computer. You can install the same by installing Samsung Kies. To download it manually, click here.

Procedure to Upgrade Samsung Galaxy S2 GT-i9100 with AOKP Android 4.1.2 Jelly Bean Custom ROM:

  • Install ICS 4.0.3 XWLPD firmware on your phone by following this guide.
  • Root and install Custom recovery (CWM) on XWLPD using this guide.

Note: If you’re coming from any other custom ROM, you can directly proceed to further installation by skipping above 2 steps.

  • Google Apps (Gmail, Maps, GTalk, Play Store etc.) are not pre-installed in this ROM. You have to download & flash it manually. Download GApps from the link given below.
  1. Google Apps (for Jelly Bean based custom ROMs).
  • After downloading ROM package & Google Apps, connect your phone to the PC. Enable mass storage mode to access SD card data. Transfer both the files on it.
  • Disconnect the phone from computer. Now, boot your device into the recovery mode. To do so, switch off the phone completely. Press & hold Volume Up + Home Button + Power Key together until recovery mode appears (you can release power button after Samsung logo appears but keep holding other two until recovery mode shows up).
  • After getting into the recovery, make a nandroid backup of your current ROM so that it can be restored in case of failure. To do so, Highlight backup and restore option in the recovery menu, select it & then choose backup to start the backup process.
  • Select wipe data/factory reset & subsequently wipe cache partition to wipe the data & caches respectively from the phone memory.
  • In the main menu, select “mounts and storage” & then select “format /system” (This won’t touch your internal/external storage).
  • Now select install zip from sdcard & then on next screen select, choose zip from sdcard. It will show you the files & folders located on the SD card of your device. Navigate to the ROM file, select it using power button (unless youre using touch CWM) & confirm the installation by pressing on Yes. This should start installing the ROM.
  • As soon as ROM installation finishes, again select install zip from sdcard followed by choose zip from sdcard. This time search for the gapps-jb-20120726-signed.zip & install it.
  • After you finish flashing both the files, Select reboot system now to Restart the phone.

Note: If you want to restore back your previous ROM, you can do this by entering into the recovery mode. In recovery, select Backup and Restore option & on next screen, select restore. Now choose the backup you would like to restore.

Excellent! Android 4.1.2 Jelly Bean based custom ROM RootBox is now up and running on your Galaxy S2 I9100. Share your thoughts with us on the newly installed Jelly Bean ROM through comments. We would be glad to hear from you.

Comments (5)
  1. Antonio March 29, 2013
    • Viraj SK March 29, 2013
  2. Sanjthedon January 8, 2013
  3. Prathamesh Billava November 28, 2012
    • Viraj SK November 28, 2012

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