This tutorial will teach you how to flash your SGS3 – Sprint version to the CM 10.1, a custom ROM developed by the CyanogenMod team that is based on the Android Jelly Bean 4.2.1 operating system.

REQUIREMENTS

1. This update is especially designed for the Sprint’s Samsung Galaxy S III (model number L710). Using this tutorial to update another version or model, may brick your device!
2. Your device has to be rooted in order to install the update and a custom recovery image is also necessary. You can use CWM or TWRP recovery, any will work.
3. Create a NAndroid backup using the custom recovery mode, to make sure you can restore to your original settings just the update is not installed successfully. It’s recommended that you also save the EFS folder, just to be on the safe side and to move your most important files to the microSD card.
4. Your device should be fully charged or at least have the battery charged at 60%.
5. An USB cable and microSD card.
6. Your antivirus or Firewall should be turned off.
7. Your warranty will be lost if you go ahead with this process, but you can later on restore it by downgrading your smartphone to stock ROM or updating it with an official upgrade.
8. We are not to be held responsible for anything that may happen to your device for following this tutorial. It’s recommended for advanced users only, so proceed at your own expense.

Updating Your Samsung Galaxy S III (Sprint Version) with CM 10.1 M1-build ROM

1. Download the CM10.1 M1 ROM and Gapps to your computer, but don’t unzip the files.
2. Connect your Samsung Galaxy S III to your computer and transfer the files you’ve downloaded to its microSD card.
3. When the transfer is complete, you can unplug the smartphone from your computer.
4. Turn OFF your SGS3 and then boot it into Custom Recovery Mode. To do so you need to simultaneously press the Volume UP, Home and Power keys. Release the keys when you see the TWRP or the CWM Recovery mode.
5. At this point you can create the NANDROID backup, in case you haven’t already. To do so, for CWM select Back-up and restore and for TWRP select Backup. Create the back-up and proceed to next step. If you have backed-up your device already or you simply prefer not to, skip this step.
6. Now select Wipe data/ Factory reset.
7. Then select Install Zip from SDcard -> select Choose Zip from SDcard and flash the Gapps for the CM10.1 zip.
8. When the installation is fully complete, select Go Back to return to the Main Menu.
9. Then select Reboot System Now and wait for the first boot process to finish loading. It should take up to 5 minutes.
10. When you’re shown the welcome screen, you can enter your Google Account details.
11. And that’s everything there is to it! You can run some tests to make sure everything runs smoothly.

NOTE: In case your device gets into a boot loop it takes too long for the boot to complete, power off your device or take out its batter - > reinsert it after a few seconds (5-10) and repeat this tutorial or just restore to the previous ROM using the custom recovery mode.

› See More: Samsung Galaxy SIII (Sprint Version): Update to Jelly Bean 4.2.1 Custom ROM