Let’s face it, you cannot expect Samsung to release an Android 5.1 update for Sprint Galaxy S3, not that it’s more than two years old. So, unofficial updates remain the only choice for the Galaxy S3 users to download and install the Android 5.1 update on their set.

Thanks to awesome developer community and AOSP code, that’s easily possible and one such unofficial update in the form of CyanogenMod 12.1 custom ROM has already hit the download for the Sprint’s Galaxy S3. There’s lot to look forward to CM12.1 ROM, btw, as it’s one of the most popular ROM to date.

What about official update release?

Official Android 5.1 update for Sprint Samsung Galaxy S3 is neither expected in development, nor in release. The custom ROMs way is the only way S3 users can get it, and that’s not bad, btw. The UI is even better than Samsung’s updates, plus the new features from Android 5.1 make it a must have.

Benefits and drawbacks of the unofficial update

Android 5.1 itself and its cool set of features and new animations is the reason good enough to install the unofficial Android 5.1 update. But when you’re getting it through a ROM like CM12.1, also add the rich, highly useful features list of the ROM too to the mix.

There are no drawbacks as such, but you have to install custom recovery which breaks warranty. Not an issue really as your S3 is already past its warranty life of one year I guess. And the custom ROMs are fully worth it, you’ll soon have a bunch of more cool 5.1 update based custom ROMs to play with. Benefits overweight the slight risk absolutely.

Removing the unofficial update?

Using the Odin software, one can easily install the official firmware back. That will remove both the custom ROM and the custom recovery. Easy.

Note: You know, because this ROM is not an official Samsung Android 5.1 update for Sprint Galaxy S3, there are chances it could contain few kinks at some corners. Any major bugs will be reported below.

Bugs
  • None
Downloads

Download the ROM file in .zip format from here, the source page where you could also keep a tab on all of the development about the ROM, and also any current issues with the ROM along with their available fixes, if any. Also download the Android 5.1 Gapps of your choice, and flash them after the ROM — they contain Google services and apps which cannot be part of the ROM.

Supported devices
  • Samsung Galaxy S3 at Sprint, model no. SPH-L710
  • Don’t try on any other device whatsoever
Instructions

Warning: Warranty may be void of your device if you follow the procedures given on this page. You only are responsible for your device. We won’t be liable if any damage occurs to your device and/or its components.

Important Note: Backup important files stored on your device before proceeding with the steps below, so that in case something goes wrong you’ll have backup of all your important files.

  1. Transfer the ROM file to your device’s internal storage and remember the location where you save it.
  2. You need TWRP recovery for this. Get it from here. There’s good instructions set there, too. For more help, Google is your friend.
  3. Boot into Recovery mode. (How to: Power off your S3 and then after 5-6 seconds, press and hold together Power+Home+Volume Up till you see Samsung logo.)
  4. Make a backup. Once in TWRP recovery, take a backup of your current ROM. Select Backup, then do a “Swipe to Back Up” on the bottom of the screen. Wait for the backup to finish, it’s a time consuming process.
  5. Wipe your device. Once the backup is finished, do this: tap on Wipe, then Advanced wipe, and then select Cache, Dalvik/ART cache and Data. Then do the “Swipe to wipe” at bottom to ready the device for ROM flashing by erasing the cache, dalvik cache and data in one shot.
  6. Install ROM now. Go back to the main menu of TWRP recovery and select Install. Navigate to the file where you saved your ROM’s zip file, select it and “Swipe to Confirm Flash” on the bottom of the screen. Now wait until the flashing process finishes.
  7. Also flash the Gapps the same way as ROM.
  8. Go to back to recovery’s Main menu, select Reboot » select System.

Your device will now reboot with Android 5.1 update, thanks to CM12.1 custom ROM.

In case you need any help over this, let us know. And, you can thank the user Lrs121 for sharing this.

Android 5.1 update is also available on: