Users of the T-Mobile Samsung Galaxy S3 SGH-T999 are in for a treat — a frozen treat, in fact — courtesy of an official Android 4.0.4 Ice Cream Sandwich via build UVALH2.

We know very little about this update.  But, it's an update!  So, we can safely presume that the update brings a lot of bug fixes, and most certainly, a few improvements and enhancements here and there to make your Galaxy S3 much better than before.

This is an official update from Samsung, which means you can get it via over-the-air (OTA) update.  Though, for whatever reason, if you prefer to manually load this up on your Galaxy S3, then by all means, give us the honor of walking you through it.

In this guide, learn how to upgrade the Galaxy S3 T999 to Android 4.0.4 ICS build UVALH2.

Warning

• The instructions in this guide are intended for use with the T-Mobile Samsung Galaxy S3, model number SGH-T999. Applying these instructions on another device or model may produce undesired outcomes.
• The information in this guide is provided for instructional and educational purposes only. There is no guarantee that these instructions will work under your specific and unique circumstances.
• Use these instructions at your own risk. We shall not hold any responsibility or liability for whatever happens to you or your device arising from your use of the info in this guide.
• Read and understand the whole guide first before actually performing the instructions.

Requirements

• T-Mobile Samsung Galaxy S3 SGH-T999
• A Windows PC
• Handset USB drivers installed on the PC. You may install the drivers by installing Samsung Kies.
• Enable USB debugging on your handset.
• Disable antivirus, firewall, and other security software. Also disable Samsung Kies and other software that accesses your phone. Such software can interfere with the procedure in this guide.
• Download Odin3 v3.04 (Odin3-v3.04.zip, 456 kB)
• Download UVALH2 firmware (T999UVALH2_T999TMBALH2_TMB.zip, 719.6 MB)
• Backup all personal data on your phone to make sure you have a copy of your personal data (e.g., contacts, SMS, MMS, Internet settings, Wi-Fi passwords, and the like) in case the procedure in this guide erases such data.
  • For backup tips, check our guides on how to sync your data to the cloud and how to create local backups of your mobile data.

Instructions

1. Extract Odin3-v3.04.zip to a folder on your computer.
2. Extract the UVALH2 firmware ZIP file to another folder anywhere on your computer. You should get the file T999UVALH2_T999TMBALH2_T999UVALH2_HOME.tar.md5.
3. Turn off your Samsung Galaxy S3
4. You need to boot your phone to Download mode. You can do this by pressing and holding down the Volume Down button, Home button, and Power button at the same time. Once the “Warning!!” message appears, press Volume Up button to proceed to Download mode.
5. Go back to your computer and locate the Odin3 v3.04.exe file. Double click on the file to launch Odin.
6. Connect your phone and computer using a USB cable and wait until Windows completes the installation of the drivers. The message “Added!!” will appear on the bottom-left corner of Odin, which means that your phone has been successfully detected by Odin.
   • Note: If this message doesn't appear, you need to reinstall your drivers on your computer.
7. Click the PDA button in Odin then locate the T999UVALH2_T999TMBALH2_T999UVALH2_HOME.tar.md5 file.
   • Note: Do not change any options in Odin except the required file in PDA.
8. To start flashing UVALH2 firmware, click the Start button in Odin. The tablet will automatically reboot, and a “PASS!” message will also appear in Odin.
9. When you see the Samsung logo, you can safely disconnect your tablet from your computer.
   • Note: If Odin gets doesn't proceed or gives you a “FAIL” message, disconnect your phone from your computer, remove the battery of your phone and place it back. Repeat the steps from step 4.

Troubleshooting

If you were able to successfully flash UVALH2 firmware but it is stuck on
the boot animation, you need to continue with the steps below. However, the steps below may delete your personal data, apps, messages and contacts.

1. Turn off your phone.
   • Note: If you are still in booting animation, simply remove the battery to turn off your phone and return the battery.
2. You need to boot your phone to Recovery Mode. You can do this by pressing and holding down the Home button, Volume Up button, and Power button until recovery boots.
   • Note: While in recovery, you can use the Volume buttons to navigate through the menu and Power or Home button to select.
3. Perform a full wipe:
   • Choose Wipe data/factory reset and confirm the action on the next screen.
   • Choose Wipe cache partition and confirm the action on the next screen.
4. Go back to the main menu and select Reboot system now to reboot your phone.

Excellent! You have successfully upgraded your T-Mobile Galaxy S3 SGH-T999 to Android 4.0.4 Ice Cream Sandwich firmware build UVALH2.