Update AT&T Galaxy S3 to CM 10 Nightlies Jelly Bean ROM

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CyanogenMod 10 is back and this time is official, as during the past few weeks we have showed you how to update different handsets with the unofficial port of the already mentioned ROM. Now, as the days will pass, we will see more and more Android powered devices ready to receive the Jelly Bean based firmware as the CM team is working hardly to satisfy all the demands. The best way to start is by providing the update to one of the most popular smartphone nowadays, the Galaxy S3. So, during the following lines, I will teach you the easiest way available for updating the AT&T SGS3 to CM 10 Jelly Bean custom ROM.

We are dealing with the official variant of CyanogenMod, the Nightlies release to be more precise, so there won’t be any problems in running the software on your device. The firmware is coming from Samsung though, so be careful as the warranty will get void once you start this operation. As you might know, each time you decide to flash a custom ROM, you must root the device first for unlocking the system and for removing the factory restrictions. Do the same for your AT&T Galaxy S3 or else you will not be able to install the CM 10 ROM on it. Furthermore, install a custom recovery image after this as you will have to use this tool on the installation procedure (it can be used for the backup process too).

Because the warranty will be void, you should be careful in what you do with your phone. Always follow a how to guide like this one, and never perform things by yourselves. The warranty can be restored but only if you are willing to downgrade to the stock ROM or to update to an official Android OS, released by Samsung and suitable for your SGS3. Of course, you will re-install the factory restrictions and the bootloader will be once more locked. Also, the root access will be revoked, so you will have to gain it back. Furthermore, before all these, you should ensure that your data is in safe hands. For this a backup is what you need.

The backup is an easy to handle operation due to the numerous apps available on the Google Play store. Also, you can use a computer or a SD card for temporarily saving the files from your device, or the Android cloud for storing the contacts and so on. If you don’t know how to use all these don’t hesitate and check out our how to section for backup guides. From there you can learn how to use backup and restore apps for saving the text messages, the contacts, the call logs, internet saves and even the current ROM (for this a custom recovery image is required).

Now, as you might know, CM 10 is a custom ROM based on the latest Android platform, the Jelly Bean one. This means that the software is including all the features from the Android OS along with many other developed by the CM team. In this way you are being able to power up the performances of your SGS3 by customizing its system. You will gain more speed, the battery life will be improved, the system will use less RAM and so on. Don’t forget though that you will not receive the classic Android interface, as the CM 10 is having its own looks.

Another thing you must check before the proper guide is referring to the preparation tasks. The so called pre requisites are vital for you as without completing them you will not be able to apply the upgrade. In the worst scenario you can even brick your phone, so don’t skip this section. Fortunately for you this is the last part of the guide, after this the steps being displayed. So, let’s get started.

  • Remember to backup, root and install a custom recovery image on your AT&T Samsung Galaxy S3.
  • Then, make sure you can use a Windows running computer, your handset and its USB cord.
  • Next, on both PC and smartphone disable the antivirus tools. Also deactivate the Firewall protection as it can interfere with the flashing procedure.
  • Enable the USB debugging option from your device.
  • And finally charge its battery or ensure that it has more the 70% power left.

Do not apply this step by step guide on other handsets similar with the AT&T SGS3 as the CM 10 ROM will not work on the same. Also, by trying to flash the OS on different devices you are risking in bricking them, so be careful in what you do and read twice before applying something on your phone.

How to Update AT&T Galaxy S3 to CM 10 Nightlies Jelly Bean ROM

  1. Download the update file from here.
  2. Download the Google Apps from here.
  3. Save the files on your computer.
  4. Connect the S3 with the PV via its USB cord.
  5. Copy-paste the files from the computer to your phone.
  6. Unplug the USB cable for disconnecting the device from the PC.
  7. Turn off the smartphone.
  8. Reboot in recovery mode by pressing on the Volume Up and Home buttons while powering on.
  9. The first thing to do is the wipe; select “wipe data factory reset” followed by “wipe cache partition”.
  10. Then, select “install zip from sd card” and “choose zip from sd card”.
  11. Pick the update file first, install it and then do the same for flashing the Google Apps.
  12. Wait until the installation process is over.
  13. Then select “+++go back+++” and “reboot system now”.

That was all; you can now use your device once more. Furthermore, now your AT&T Samsung Galaxy S3 is running the Nightlies version of the official CM 10 custom ROM firmware. Give it a try, test the new ROM and return here for sharing the impressions with us and with other users. Also, tell us if you have any other questions or issues related to the Android topic and we will do our best in order to help you out.