Android 4.1.2 Jelly Bean Avatar ROM For T999 Galaxy S3 T-Mobile–Ultimate Guide

Android 4.1.2 Jelly Bean update now possible on your T-Mobile Galaxy S3 SGH-T999 and all thanks to Avatar custom ROM. We do shared few Android 4.2.1 Jelly Bean ROM for this smartphone but many of you may still prefer to run Android 4.1.2 Jelly Bean based ROM as it spend more time already in development and hence more stable. The key attraction point of Avatar ROM is, it bring customization of CM10 custom ROM but along with it also provide the theme engine of MIUI custom ROM. So, by installing Avatar ROM you will get all customization of CM10 Android 4.1.2 Jelly Bean custom ROM as well as can install eye candy themes of MIUI ROM. Read through this article to learn necessary steps to update your T-Mobile Galaxy S3 T999 to Android 4.1.2 Jelly Bean based custom firmware Avatar ROM.

Note: This Avatar ROM based on Android 4.1.2 Jelly Bean is still under development and may contain bugs and issues. All issues will be resolved as development progress.



This tutorial is only for Galaxy S3, model number T999. Don’t try this guide in any other Android device. Check your device’s model number in: Settings » About phone. Also, we are not responsible for any damage caused due to the instruction given in this page. Try this at your own risk. Although, it is very unlikely that your device will be damaged if you follow all the instructions as it is which are mentioned in procedure.

Pre Requisites:

Backup your data first using below mentioned instructions, so that if you lost any data you can recover it easily.

SMS & Call LogUse SMS, MMS & Call Log Entries Backup & Restore App
Contacts & SettingsUse Android default backup options.
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


  1. Make sure your device have at least 80% battery power. [How to Check Battery Percentage in Android Phones]
  2. You already have USB Driver Installed for Samsung Galaxy S3 T999 in your PC. [USB Driver].
  3. Backup your EFS Folder. [Guide]
  4. Make sure USB Debugging is enabled. [Guide].
  5. Your device have ClockworkMod Recovery Installed [Guide].

If you done everything that we mentioned above then you are ready to move in the next page of this guide where we compile an easy to follow step-by-step guide on how to install Android 4.1.2 Jelly Bean based Avatar ROM on Samsung Galaxy S3 T999.

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