Update Sprint Samsung Galaxy S3 with Unofficial CyanogenMod 11 Android 4.4 custom ROM

Flash Unofficial CM 11 Android 4.4 ROM for Sprint Galaxy S3

The Sprint variant of Galaxy S3 has received an unofficial build of CyanogenMod 11 KitKat. Use this tutorial if you want to learn how to successfully update your device.

At the moment there are some things that aren’t working in this release like the Camera that causes reboots. If you want to learn more about this custom ROM build, then you should take a look at its dedicated XDA thread here. Check the guidelines below before starting the installation process:

  • Use this post only with the Sprint variant of Samsung Galaxy S3.
    – don’t attempt to use this tutorial for any other smartphones, as you will end up bricking their firmware.
  • Your device has to be factory unlocked, rooted and running a CWM Recovery image.
  • Before installing the new ROM you will be forced to apply a Factory Reset process, which means that you will lose all data that is stored on your phone’s system partition.
    – internal and external storage won’t be affected by this tutorial.
  • Make sure that you’re running the latest CWM Recovery 6.0.4.3 version.
  • If you want to backup data from installed apps then you should use the Helium tool from Google Play Store here.
  • Backup data from SMS and APN Internet Settings using the following tools for Android: SMS backup & restore | APN Settings Backup & Restore. Root access is required for these apps.
  • Sync contacts info with your default Gmail account.
  • - if you don’t know how to do it, then you can use this info here.
  • Enable USB Debugging from Developer Options menu.
  • Create a full NANDROID backup of your currently installed ROM.
    – this will set a restore point for your device and you will be able to use it in case the new ROM doesn’t boot in normal mode.
  • Make sure that your phone’s battery has enough power left before starting the installation, so that it won’t switch off in the middle of the updating process.

Since you’ve gone past all of the above, continue to the next part of this post. Make sure not to skip any steps and that you know what you’re doing.

We cannot be blamed in case you brick the phone or lose any data in the process. For any extra help use the comments section.

How to flash Unofficial CM 11 KitKat custom ROM for Sprint Galaxy S3:

  1. Download the custom ROM zip from here.
  2. Download Gapps for this custom ROM from here.
  3. Connect the smartphone with your computer, then move both files to your device’s internal storage.
    – after the zips are moved you can disconnect the smartphone from computer.
    – don’t unzip the contents of these files.
  4. Power off your Sprint Galaxy S3 now.
  5. Boot your phone in CWM Recovery Mode
    – if you don’t know how to do it, then you can find more info here.
  6. First thing that you need to do is to create a full NANDROID Backup for the ROM that is currently installed on your device.
    – select ‘backup and restore’, save the file on your device and then continue to the next step.
    – this step shouldn’t be skipped, as it will create a restore point for your phone, one that can be used in case the new ROM doesn’t boot in normal mode.
  7. Now you can apply the wipe data/ factory reset step.
    – select ‘wipe data/ factory reset’, confirm the process and get to the next step in order to learn how to flash a custom ROM.
  8. Next, select ‘install zip from sdcard’ and then ‘choose zip from sdcard’ option. Find the Unofficial CM 11 custom ROM zip and flash it.
    – don’t press any buttons until all files are installed.
  9. After the installation is complete you will have to repeat step 8 actions and flash Gapps zip.
    – don’t skip the Gapps installation.
  10. When you do manage to complete the installation of both files, return to the main custom Recovery menu.
  11. Now you should reboot your smartphone in normal mode.
    – note that the first boot process of this new ROM takes a while to complete, which is why you shouldn’t press any buttons until you see the new home screen.
  12. Enter your Google Account details and take control of your phone when the boot is complete.
  13. Now you can start testing all the new features and functions added with Unofficial CM 11 ROM.

NOTE: in case the first boot of Unofficial CyanogenMod 11 doesn’t complete in under ten minutes, then you will need to remove the phone’s battery and then repeat the entire tutorial. Re-insert the battery and then you have to make sure not to skip any steps that I’ve listed above.

Since you’ve applied all of the above and you did manage to install the new ROM, then you’re now free to test and see how is your smartphone working with this brand new OS. If you have any other questions regarding the installation process, then you should post them in comments.

Also, if you don’t like how your Sprint Galaxy S3 works with the Unofficial CyanogenMod 11 custom build, then you can use the NANDROID Backup file created in step 6 and restore your phone to its previous status. Remember that these tasks should be performed by advanced users, as this custom ROM is still in its testing phase and you might find some errors and bugs while going through its features.

  • Dennis Caunce

    Not working. getting assert failed. after Googling, i figure I have to update the bootloader first. Can you point me in the right direction for this?