How to upgrade the Galaxy S3 I747 to Android 4.0.4 ICS build UCALH1

Someone spilled some ice cream — unfortunately, not jelly beans — for the AT&T Samsung Galaxy S3 SGH-I747. A leaked update for Android 4.0.4 Ice Cream Sandwich build UCALH1 has surfaced recently.

Even though it is not Android 4.1 Jelly Bean, the leaked update is always welcome for those who are seeking to get their AT&T Samsung Galaxy S3 firmware up-to-date. However, there is no changelog or record of changes as this is a leaked firmware.

Though the updated firmware has been reported to be stable and excellent for daily use, there may also be some bugs that you could encounter. After all, this is leaked firmware. And, although it is “official” firmware, it does not carry the imprimatur of either AT&T or Samsung, since it has not yet been officially pushed out to the public.

In addition, since this is an official firmware, the binary flash counter will not increase.

In this guide, learn how to upgrade the Galaxy S3 I747 to Android 4.0.4 ICS build UCALH1.

Warning

The instructions in this guide are intended for use with theAT&T Samsung Galaxy S3, model number SGH-I747. Applying these instructions on another device or model may produce undesired outcomes.
Flashing this firmware will replace your phone's current bootloader. It will also wipe your phone's internal SD card.
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

AT&T Samsung Galaxy S3 SGH-I747
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 the UCALH1 update (Download I747UCALH1_OneClick_common.exe, md5sum: 6A99DFF8CCC886757E63ED3A556D1D99)
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

Turn off your phone.
Boot your Samsung Galaxy S3 into Download Mode. You can do this by pressing and holding down the Volume Down, Home, and Power buttons until the screen shows a warning message. Press Volume Up to enter Download Mode.
Double-click the downloaded UCALH1 update EXE file on your computer to launch Odin.
Connect your Samsung Galaxy S3 to your computer using the USB cable and wait until drivers are fully installed. You should be prompted by Odin’s message box with the word “Added!” This is an indication that your Samsung Galaxy S3 has successfully connected to your computer.
- Note: If the message “Added!” doesn't appear, you need to reinstall the USB device drivers and repeat step 4.
Click on the Start button in Odin to begin flashing the firmware on your phone. Once the installation is complete, your phone will automatically reboot. When the Samsung logo appears on the screen, you can now safely disconnect your phone from your computer. You will also see a “PASS” message with a green background in the top-left box in Odin.
- Note: If Odin doesn't continue or freezes and you get a “FAIL” message with red background, completely disconnect your phone from your computer then close Odin. Remove the battery of your Samsung Galaxy S3 then place it back again. Repeat the steps from step 2.