Update Galaxy S3 I9300 to XXUFMB3 Android 4.2.1 Jelly Bean Official Test Firmware

• Last modified: Android Tips

XXUFMB3 Android 4.2.1 for the Samsung Galaxy S3 I9300 is finally here! Android 4.2.1 firmware is the latest Jelly Bean that is soon going to be available for this phone, however, the first test release is now available for download. You can not download this firmware from Samsung KIES, because it is a private test firmware that has been leaked online (by SamMobile) and everyone can experience what is Samsung planning to add in the Android 4.2.1 Jelly Bean firmware update. In order to install this I9300XXUFMB3 firmware, your Galaxy S3 does not need ClockworkMod Recovery installed or root access because we will use ODIN. You can easily update Galaxy S3 I9300 to XXUFMB3 Android 4.2.1 official firmware. You can also root Galaxy S3 on this firmware.

As you continue reading below, we will guide you how to install XXUFMB3 Android 4.2.1 Jelly Bean on Galaxy S3 I9300 using ODIN, tell you how to backup your important data and have given some other important tips. We don’t want anyone losing their data during the installation process. Please note, this is not an official firmware release for the public by Samsung. It is a test firmware that was available to selected beta testers. This firmware is a completely unbranded firmware which means any Galaxy S3 I9300 user can install this on their phones. Let’s continue with the tutorial now.

Disclaimer: All the custom ROMs and firmwares, official software updates, tools, mods or anything mentioned in the tutorial belong to their respective owners/developers. We (TeamAndroid.com) or the developers are not to be held responsible if you damage or brick your device. We don’t have you on gun point to try out this tutorial ;-)

Android 4.2.1 XXUFMB3 Firmware Details:

Android Version: 4.2.1 – JOP40D (Jelly Bean)
PDA: I9300XXUFMB3
CSC: I9300OJKFMB3
MODEM: N/A
Region: Middle East
Carrier: Unbranded
Changelist: 171637
Build Date: 19th February 2013

ROOT TUTORIAL: How to Root XXUFMB3 Android 4.2.1 on Galaxy S3 I9300 Official Firmware.

And if you wonder why you should root? Read: Benefits of Rooting Your Android Device.

A warning message has been given by SamMobile regarding this firmware. And like we have said this before, this is a test firmware that has been leaked, not an official release of Android 4.2.1 for the Galaxy S3 I9300.

We have repackaged this firmware into an ODIN Flashable firmware ourselves from the dump files we took from Saturn’s device. This firmware will increase your binary counter, if you don’t know what this means then don’t flash this firmware. This Firmware will also change your device status to Modified. This firmware doesn’t contain any Modem so the Modem you are using before flashing this firmware will remain. This is a PRE-RELEASE version so not official from KIES. As this is a PRE-RELEASE firmware some minor bugs are to expect.

We have FULLY TESTED this firmware and this firmware works perfectly as any other official firmware.

Android 4.2.1 XXUFMB3 Firmware Features:

Here is a list of the amazing new features Android 4.2.1 offers on the Galaxy S3:

  • Android 4.2.1 – JOP40D
  • Improved Ripple effect on Lockscreen
  • New Android 4.2.1 Lockscreen with widgets
  • Daydream (Settings>Display)
  • New Additions in Notification Center
  • Notifications are more actionable
  • Voice Command (Let’s you control various parts of the phone using voice commands)

Samsung Galaxy S3 I9300 - XXUFMB3 Android 4.2.1

Samsung Galaxy S3 USB Drivers

You will need to connect your Android phone with the computer. For that, please make sure you have installed the USB drivers for Samsung Galaxy S3 properly. If not, you can download the latest official drivers from our Android USB Drivers section here:

Download Samsung Galaxy S3 USB drivers!

Backup and Other Important Tips

Done with the USB drivers? Perfect. The tutorial is on the next page, but first, please take a look at the following tips and important points you need to take care of. These are important, as we don’t want anyone losing their personal data or apps:

Always backup your important data that you might need after you install a new custom ROM, an official software update or anything else. Make a backup for just in case, you never know when anything might go wrong. See below for some tips on how to backup data:

Samsung users can also back up data using Samsung KIES. If you backup data manually, you get more options what to choose from and it is very easy to move data across Android devices from different manufacturers, i.e moving Samsung Galaxy Note backup data to HTC One X.

If you already have a custom recovery (ClockworkMod, TWRP etc.) installed on your phone, we strongly recommend a backup using that as it creates a complete image of your existing phone set up.

A few more optional tips that you should remember:

1. Having problems connecting your Android phone to the computer? You need to enable USB debugging mode. See here: How to Enable USB Debugging — for Gingerbread, Ice Cream Sandwich and Jelly Bean.

2. Make sure your Android device is charged up to 80-85% battery level. This might help you: How to Check Battery Percentage. Why? Because, if your phone goes off suddenly while installing a custom ROM, flashing an official firmware update or installing mods etc. — your phone might get bricked or go dead permanently. No one wants that, right?

4. Most of the tutorials and how-to guides on Team Android are for factory unlocked Android phones and tablets. We recommend NOT to try our guides if your phone is locked to a carrier, unless we have specified the carrier name or device model.

If you find the above tips useful and they were helpful to you, please consider giving us a +1 or LIKE to thank us!

All set and ready? Good. You can now head over to the next page and update Galaxy S3 I9300 to Android 4.2.1 XXUFMB3 official firmware update.


  • clark

    messaging is not working on this version .
    please fix the bug

  • Sami

    I installed teh 4.2.1 its amazing with the dual screen option
    but SMS will not open .. it will crash everytime … so i’m rolling back till this is fixed

  • jesus

    fully tested? I guess you don’t use SMS much then, huh?

    rolling back…

  • qing

    sms doesnt work.
    multi-window doesnt work.

  • Sami

    @ff21ab61578c14834c635c82dfae887a:disqus if you disable and enable the multi window from settings.The drag button will appear on the left of the screen then u can try it . i forgot to mention this problem too earlier .

    • qing

      thx a lot….but i have already restored to 4.1.2….I think maybe I should wait for the newer official ROM.

  • Nicole Badran

    Hey guys, thanks for the galaxy s3 android 4.2.1 update but as soon as I updated it I faced 2 problems:
    1- constant vibration even though I set all notification to never vibrate
    2- messaging is not working at all the app is crashed it is closing when I try to access it and I am not receiving sms anymore

    please advice a solution asap.
    reply to my email: soul_agony@hotmail.com

  • Max Dick

    You idiots that don’t read carefully the instructions… do a full data wipe and then SMS app will work as good as always…