How to Update Galaxy S2 GT I9100 with RootBox Jellybean 4.1.2 Firmware

Galaxy S2 LogoAfter Galaxy Nexus, Nexus 7, Samsung Galaxy S3 received its share of first builds of Jellybean 4.1.2 firmwares, it’s time for Samsung Galaxy S3 smartphone users to update with the latest jellybean 4.1.2 firmware update. Though this is not an Official firmware released by Samsung, this is a custom ROM firmware developed by the third party developers. This custom ROM firmware is brought to your by the Root Box team, all thanks to bajee11 for developing the firmware. So, before proceeding, we will be checking out on how you can apply this update with the help of pre requisites and a detailed procedure.

Note: This update should be strictly applied to the Galaxy S2 GT I9100 variant only and not to any other variants like I9100G etc. as it may even brick your device for which we should not be held responsible.

Express Pre Requisites:
First up you will have to make sure that your Galaxy S2 device is rooted, this can be checked with the help of “Root Checker” app from the Google PLAY Store. If your S2 is not rooted, you will have to follow the below mentioned 2 steps so as to root the device. Also, once the device is rooted, download and install the “ROM Manager” app from the Google PLAY Store itself.

How to Update Samsung Galaxy S2 GT I9100 with Official ICS 4.0.4 XWLPO Firmware

How to Root Galaxy S2 GT I9100 on ICS XWLPO 4.0.4 Firmware

Disclaimer: Follow all the instructions mentioned in this article as if there is any damage caused due to not following instructions then we shall not be held liable or responsible. Just in case if you face any issues then we will try our level best to address the same.

Your precious data should be backed up so as to make sure that just in case if the data gets erased / corrupted, you should be in a position to restore the same. So, with the help of below mentioned manual steps you will have to create the backup.

SMS – Use “SMS Backup & Restore app”,
Contacts – Sync with the Gmail application,
Call Log - Call Log and Restore
Images, Songs, Videos, Files – Copy to internal / External SD Card,
APN and MMS Settings – Note down from the path “Applications > Settings > Wireless and Network > Mobile Networks > Access Point Names

From the path “Settings > Applications > Development > USB debugging”, enable the USB Debugging, ensure that the USB debugging option is ticked in your Samsung GalaxyS2 smartphone. Minimum battery level left in your phone should not fall below 30% so as to make sure that it doesn’t get turned Off in the middle of firmware update.

You will be requiring the external SD Card with almost 1 GB of free space so that the custom ROM firmware package can be placed in the same. Disable / uninstall all the antivirus tools present in your device as it may interrupt the process of firmware update.

Features of Root Box Jellybean 4.1.2 Firmware:

  • Based on JB 4.1.2 – Built from RootBox Sources (Teamhacksung, CM & AOKP)
  • HSPA+ Support
  • A2DP Support
  • T9 Dialer
  • Cherry picked fixes from CM
  • OTA Update
  • ExTweaks integrated in Settings – if ExTweaks installed in /system/app
  • Init.d Support
  • AOKP Features

Assuming that you are done with the above mentioned steps, you can now head over to the next step where we have summed up a detailed guide on how to apply with this firmware update.

  • Mick Merritt

    Flashed as soon as you released the article. Been v stable

  • Minh

    please is this only for Galaxy S2 ?? because i see this ” … Recovery mode in Galaxy S3 GT I9300 can be …” in part 2 ???

  • saquib

    can i update s2 directly from gb jpkj2

    • Pradeep Neela

      yes you can apply this update

  • satyen

    Hi Pradeep, is this a stable JB rom for the S2, with all the JB features

    • Pradeep Neela

      yes its the stable firmware

  • shakir

    I want to update my galaxy s2

  • mohammed zuber

    while updating custom rom rootbox jellybean 4.1.2 version my mobile screen goes black with white stripes……please help me

  • Manoj


    Is the above mentioned ROM is stable? I am having Jelly BEan 4.1.1 I9100XXLQ5, Pls advice if i can update with this ROM??

  • Manoj

    Procedure heading shows the Custom ROM is for S2 and the in some places the procedure shows for S3.. Kindly update.

  • UKT

    Is this faster than the 4.1.1? And can this one read the memory card? Because the previous version can’t. :)

  • avinash

    followed each and evry instruction very carefully, even though my phone got dead. i cant even turn on my phone

  • Imtiyaz

    Hi Pradeep
    I am not able to browse to my external SD card after the JB Upgrade, kindly advise

  • ROY

    dont waste your time. WiFi is not working

  • rigjohn

    is it faster than ICS, and better life on battery?
    Any problems with camera, or anything else?

  • Kaung Htet Oo

    battery life span is too short than in ics.

  • Stephen Scott

    Can’t get WiFi to switch on

  • nishant

    wi-fi not working

  • Piyush Ranjan

    I am presently on rooted ICS 4.0.4 XWLPO. Can I update and after update the root accesses will be there or revoked.

  • chengareddy.avula


  • DaaC

    Installed last night from Gingerbread to JB 4.1.2 without any problem. Took just 10 min all up.

    >Not able to restore from Titanium backup
    >miss my allshare app [help pls]
    >no music/video player
    >[IMO]first time JB users may struggle with the setting options

  • EMMA

    after successful update phone gets stucked displaying a logo stating root box is taking longer than usual and even after re inserting the battery

  • bazzorro

    What about gps and battery life…..

  • rahul

    which one package to download
    here shown too many

  • Anup Dcruz

    Hi Pradeep does this firmware support facebook contact sync as pervious JB version’s doesnt support it.. plz update us

    • Pradeep Neela

      yes it does support