You can update your Sprint variant of Samsung Galaxy S3 (SPH-L710) to the new Android 4.2.1 Jelly Bean using custom ROM Slim Bean Beta 1. The Slim Bean Beta 1 ROM brings many features to Galaxy S3.

According to an Android Jinn report, the exclusive Android 4.2.1 Jelly Bean features include new quick settings option, multi-user support, improved Google Now, new camera app, gesture typing, miracast display, lock-screen widget, new daydream feature, photo sphere and many more.

The report stated that the Slim Bean Beta 1 is known for low file size and fast speedy nature. It further warned that users may face some bugs as it is still under development; however, these issues are expected to be fixed as development progresses.

Major features of the Slim Bean Android 4.2.1 Jelly Bean Beta 1:

Dotted Battery Mod and color picker

Battery bar mod

Notification Background customization

Notification row transparency

Quick Settings for

Network mode tile

Profile Tile

Dismiss on toggle

Updated APN + SPN

Wifi name in notification drawer

Power widget

Device Parts

Performance Settings (need to tap build number a few times)

Cursor control using volume keys

Disable full screen keyboard

Alternate app chooser

Clock styles and color chooser

ADB over wifi

Camera power shutter mod

Wifi country specific settings

Notification IME selector

SMS quick reply & mark as read from notification

All MMS features

All Contacts features

Note:

This tutorial is only for Sprint variant of the Samsung Galaxy S3. Therefore, this should not be tried on any other Android devices. IBTimes cannot be held responsible if anything goes wrong. Proceed at your own risk. Below is the step-by-step tutorial showing how to install Android 4.2.1 Jelly Bean on to Sprint Samsung Galaxy S3 (SPH-L710) using Slim Bean Beta 1 ROM. Before you proceed, take a note of the prerequisites you need to be aware of:

- We advise you have a proper backup of your important data.

- Ensure that your device has at least 80 percent battery power.

- USB driver must be installed for Samsung Galaxy S3 (SPH-L710) in your PC.

- USB Debugging must be enabled.

- Backup your EFS Folder.

- Your device must be rooted and have ClockworkMod Recovery Installed.

- Flashing this ROM on Galaxy S3 L710 will increase your binary counter.

- Make sure you don't skip Nandroid backup as it's very helpful if this custom ROM doesn't work the way you want.

Files Required:

1. Slim Bean Beta 1 4.2.1 Jelly Bean ROM For Galaxy S3 L710 [Filename: Slim-4.2.1.Beta.1-d2spr-20121222-0812-OFFICIAL.zip]

2. Google Apps [Filename: Slim_Gapps.zip]

The Procedure:

Step 1: Connect your Sprint Galaxy S3 smartphone to PC using USB cable.

Step 2: Copy downloaded files to the SD card of your phone without extracting any.

Step 3: Disconnect USB and turn off your phone.

Step 4: Boot into ClockworkMod recovery in your Galaxy S3 by pressing and holding the Volume Up, Power and Home buttons together until the Samsung logo appears on screen. Leave the buttons and hold then again. At this point, you will receive ClockworkMod recovery screen. Now browse between options in recovery using Volume keys while using Power key to select an option.

Step 5: Perform a Nandroid backup of your existing ROM by selecting Backup and Restore, then on the next screen, selecting Backup again. Return to the main recovery menu after back up is complete.

Step 6: Perform the data wiping task now. You can do it by selecting wipe data/factory reset, then select Yes on next screen to confirm your action. Wait for a few minutes till the data wipe is completed.

Step 7: Select install zip from SD card and then select choose zip from SD card. At this point, locate the Slim-4.2.1.Beta.1-d2spr-20121222-0812-OFFICIAL.zip file and select it by pressing Power button (tap on it if using touch version). Confirm installation by selecting Yes  -  Install _____.zip on the next screen. The ROM installation will begin.

Step 8: After the ROM installation is done, repeat step 8 but choose the Slim_Gapps.zip file instead of ROM zip to install the Google apps package.

Step 9: Once the installation is completed, return to the main recovery menu and select reboot system now to reboot the phone and boot up into customized Android 4.2.1 Jelly Bean ROM Slim Bean Beta 1. This step might take a while to complete.

Step 10: If you want to return to the previous ROM: You should go back to your previous ROM, boot into recovery, select backup and restore,  then restore your previous ROM by selecting it from the list.

[Source: Android Jinn]