Leaked Official Android 4.2.1 I9300XXUFMB3 Firmware for Samsung Galaxy S3

The entire world is now waiting for first glimpse of Samsung Galaxy S4 which Samsung is going to unleash in this month. Samsung is so busy in this whole process of launching successor of their bestseller Galaxy S3 that in meantime they havent paid much attention on giving official firmware updates to their previous devices.

Its been several months since Google released their upgraded version of Jelly Bean that is Android 4.2.1 but still no official update is provided by Samsung. On the other side there are number of custom ROMs available based on this update for latest devices like Galaxy S3, Note 2 etc.

But now wait is over for Galaxy S3 users. If you dont want to go for custom ROMs and believe in official firmwares, an official Android 4.2.1 firmware is leaked. You can manually download and flash it. Here are some key features of this firmware:

  • Improved Ripple effect on Lockscreen
  • Widgets on lockscreen
  • Daydream
  • New additions in Notification Center
  • Notifications are more actionable
  • Voice Command (lets you control various parts of the phone using voice commands)

And being an official firmware there is less chance of having any bug present in this firmware.

This is an official firmware but it is leaked so if you dont want to go for it, you can always wait for official update release from Samsung themselves. Following article will explain you the process of manual installation of firmware.

Disclaimer: The steps mentioned in the given article are considered as risky and may cause damage to your mobile. It is recommended that you should not follow the given article if you are unaware of all these things. Carefully follow steps at your own risk. We or developers cannot be held responsible for any damage cause to your mobile.

Official Android 4.2.1 for Galaxy S3

The given article is strictly intended for Samsung Galaxy S3 I9300. Implementation of this article to any other model or variant might give you undesired results. Even permanent damage can cause to your mobile.


  • Charge your device up to 75% battery level.
  • It is highly recommended to backup all your data from internal memory (includes contacts, messages (SMS/MMS), call logs, Internet APNs etc.). Your phone data will get lost after installation of this firmware (excluding External storage).
  • 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 Update Samsung Galaxy S3 I9300 withXXUFMB3 Jelly Bean Firmware (Android 4.2.1):

  • Download flashing program (Odin Multi Downloader v3.07) & Jelly Bean 4.2.1 Package from the links mentioned below :
  1. Odin Multi Downloader v3.07
  2. Download Android 4.2.1 I9300 XXUFMB3 for Galaxy S3
  • Extract firmware package (.zip file) to any convenient location on your computer. You will find file namedI9300XXUFMB3_I9300OJKFMB3_HOME.tar.md5.
  • Switch off the phone completely. Enter into download mode. For doing the same, press & hold Volume down + Home button (Middle one). While holding both buttons, simply press Power key till you see the construction Android robot & a yellow triangle.
  • Open Odin Multi Downloader tool on your Computer which you’ve just downloaded & connect the phone using USB cable.
  • If your phone is connected successfully, youll see that the ID:COM section (located at top left) is turned yellow with a random COM port number appeared below it. (If your ID:COM box doesnt turn out to be yellow, don’t worry. You will need to install proper drivers for your device. For installation of drivers, use the CD you got at the time of purchase & install Kies software from it. You can download kies from here OR you can manually download it from here).

  • In Odin, select PDA tab & choose I9300XXUFMB3_I9300OJKFMB3_HOME.tar.md5 file. Keep all the remaining options as they are & make sure that Re-Partition box is not checked.
  • Press Start button to initiate the flashing process of Android 4.2.1 Jelly Bean firmware on your Galaxy S3. When flashing process finishes successfully, youll get Pass message with the Green background & device will restart automatically.
  • Unplug the device from Computer.
  • Now you will need to factory reset the phone in order to avoid boot loops & malfunctioning of the phone.
  • To factory reset, youll have to boot in the recovery mode. The same can be achieved by following some simple steps.
  1. Switch off the phone (you can do this by removing battery or pressing power button).
  2. Press & hold Volume up + Home button together & then press Power key. You can release Power button as soon as Samsung logo appears.
  3. Your device is now booted into recovery mode.
  • Since touch wont work in recovery, use Volume up/down & power key only for navigation & selection respectively.
  • Now highlight Wipe data/factory reset by using Volume buttons & select it using power key. The same you have to do with Wipe Cache.
  • After getting done with all these things, select reboot system now option to restart the phone.
  • You may see that the phone is booting slowly than usual but dont worry it’s normal & this is for the first time only.

Nice Job! Android 4.2.1 Jelly Bean (XXUFMB3) issuccessfully running on your Samsung Galaxy S3. Now you can enjoy all the latest features of Jelly Bean 4.2Report ushow it is working for you via comments.

Comments (6)
  1. JACKSON October 9, 2013
  2. puty June 1, 2013
    • Sanket June 2, 2013
  3. Jimmy April 7, 2013
  4. Jimmy April 7, 2013
    • Shreyas April 7, 2013

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