Samsung Galaxy S3 On AT&T Gets Android 4.2.2 Jelly Bean Update Via CM 10.1 M3 ROM (How To Install)

Owners of the Galaxy S3 on AT&T who want to get a feel for the Android 4.2.2 Jelly Bean OS before the official update is pushed out by the carrier are in for some good news. The CM10.1 M3 custom ROM will now let users of the AT&T Galaxy S3 SGH-I747 update their device from Android 4.1.2 to Android 4.2.2.

This custom ROM is a nightly build and post installation, so a possibility exists that your Galaxy S3 may get some bugs. Since this is not an official Jelly Bean update, you will require custom recovery like ClockworkMod to flash the ROM and Google Apps zip files on your device.

Here's a step-by-step guide to help you install Android 4.2.2 on your AT&T variant of the Galaxy S3.


- Remember that the instructions are applicable only for use with the Galaxy S3 SGH-I747. Flashing the ROM on any other device may brick your smartphone. Verify the device's model number by navigating to Settings > About Phone.

- Remember to read through the instructions before beginning.

- Remember to back up important data.

- Ensure your phone's battery power is at least 85 percent, if not fully charged, to avoid disruption due to power loss.

- Users should note that the instructions given in this guide are meant for reference purpose only and do not cover any warranty claims involving device damage or issues arising out of installing the firmware on your Galaxy S3. Users are advised to proceed at their own risk. iTechPost takes no responsibility for any damage or issues you may encounter with your smartphone, including bricking your device


- Ensure that you have installed the USB drivers for the Galaxy S3 SPH-L710 on your PC properly.

- Enable USB debugging mode on your phone.

- Ensure that your phone is rooted with ClockWorkMod (CWM) installed on it.

Files Required 

- Download CM10.1 M3 Android 4.2.2 ROM.

- Download Google Apps.


Step 1: Connect your Galaxy S3 to the PC using the USB cable.

Step 2: Next, mount the storage and copy the downloaded CM10.1 M3 Android 4.2.2 ROM to your phone. Do not extract any files.

Step 3: Next, switch off your device and disconnect it from the USB cable.

Step 4: Switch on your phone while pressing and holding the Volume Up, Home and Power buttons together until the device boots into Recovery mode. (Use the Volume buttons to scroll between the options and Power button to select).

Step 5: Next, in the Recovery mode perform a backup of the existing ROM. This is done so that you can restore later in the scenario that the new one doesn't work.

Step 6: To perform the backup select "Backup and Restore" and select "backup" again on the next screen. Return to the main recovery menu once the backup is complete.

Step 7: Next, perform data wiping to avoid a clash between the new ROM and the older one. To do this follow these steps:

- Select "Wipe data/factory reset".

- Next, select "Yes" to confirm the action.

- Wait till the data wiping is done. Once the wiping cache partition process is through, select "Wipe Dalvik Cache" under "Advanced" option. Go back to the recovery menu once done.

Step 8: Next, scroll down to "install zip from SD card" and press the Power button to select the same. Select "choose zip from SD card" and select CM10.1 M3 Android 4.2.2 ROM using the power button.

Step 9:  Confirm the installation by selecting Yes > Install. The procedure should start now.

NOTE: Repeat steps 8 and 9 for the Google Apps zip file.

Step 10: Once the installation is complete, select "Go Back" and reboot the phone by selecting "reboot system now" from the recovery menu. The phone will boot now and may take about 5 minutes, so wait until the process completes.

You now have the CM10.1 M3 Android 4.2.2 Jelly Bean installed on your AT&T Samsung Galaxy S3. Verify the firmware version by going to Settings > About Phone.

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