The Android development community has been busy the past couple of weeks due to the release of the Android 4.1 Jelly Bean source code. One of the familiar names in the custom ROM development scene that has appeared in every update is CyanogenMod. The reason behind its growing popularity is the fact that CyanogenMod ROMs are just plain awesome when it comes to performance tweaks and upgrades.

One of the latest updates to spring out of the CyanogenMod team goes to the AT&T Samsung Galaxy S3 SGH-I747 in the form of the CyanogenMod 10 custom ROM, based on Android 4.1.1 Jelly Bean. Nightly ROMs are continuously updated every night, compared to normal custom ROMs that are updated every few weeks or even months. The advantage of nightly builds is that you will always stay ahead of the pack and they are easy to update.

This guide shows you how to upgrade the Galaxy S3 I747 to Android 4.1.1 Jelly Bean via CyanogenMod 10 nightly ROM.

Warning

• The instructions in this guide are intended for use with the AT&T Samsung Galaxy S3, model number SGH-I747. 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

• Rooted Samsung Galaxy S3 with ClockworkMod Recovery installed.  Need help with rooting and installing ClockworkMod Recovery? You can refer to these guides:
  • • Samsung Galaxy S3 SGH-I747 (AT&T): How to root and install BusyBox
    • Samsung Galaxy S3 SGH-I747 (AT&T): How to flash ClockworkMod Recovery
• Download the following files and save them to your computer.
  • CM10 nightly for the AT&T Galaxy S3 (cm-10-20120828-NIGHTLY-d2att.zip, md5sum: d7aa8a2a9448c4b386793b0bebd49527)
  • Google Apps Package | Mirror (gapps-jb-20120726-signed.zip, md5sum: f62cfe4a827202899919fd932d5246d7)
• Fully charged battery or at least 70% battery left.
• 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. Copy the downloaded ZIP files and save them to your phone's internal SD card.
2. Switch off your phone.
3. Boot into ClockworkMod Recovery. You can do this by pressing and holding down the Volume Up, Home, and Power buttons together until recovery boots.
   • NOTE: While in recovery, use the Volume buttons to navigate and Power button to select an option.
4. Create a NANDroid backup to backup your current ROM. In case there is something that doesn't work out with this ROM, you can always revert to your old ROM. To perform a backup, select Backup and Restore and on the next screen, select Backup again. Head back to the main recovery menu once backup is complete.
5. Select Wipe data/factory reset. Select Yes on the next screen to confirm data wipe.
6. Select Install ZIP from SD card, then select Choose ZIP from SD card. Browse for the downloaded CM10 ROM file and select it. Confirm the installation by selecting Yes on the next screen. It may take a couple of minutes for the ROM to finish installing.
7. Repeat step 6, but this time around select the gapps-jb-20120726-signed.zip to install the necessary Google Application package.
8. Head back to the main menu by selecting Go back and reboot your phone by selecting Reboot system now.

Congratulations! You have successfully installed the CyanogenMod 10 nightly build on your AT&T Galaxy S3 SGH-I747.