Flash Leaked Android 4.3 UCUEMJ6 Jelly Bean ROM for AT&T Samsung Galaxy S4 I337

Update Galaxy S4 to Android 4.3

Android 4.3 UCUEMJ6 firmware has been leaked for the Samsung Galaxy S4 AT&T, and now you can use this post in order to learn how to successfully flash the ROM. Read the entire post and you should be able to complete the installation in no time without bricking your device.

The Android 4.3 brings tons of improvements, but note that the build you’re about to flash is a pre-release version and it might not be very stable. That is why you should only install it for testing purposes. Before starting the install process of UCUEMJ6 Android 4.3 test firmware for your Galaxy S4 AT&T you will need to take a look at the preparation guide below:

  • Use this post only for the AT&T model of Samsung Galaxy S4. The phone’s model version is SGH – I337.
    – don’t try to update any other Galaxy S4 variants with the files you find in this post.
  • Your phone has to be rooted and running a custom Recovery image.
    – both CWM and TWRP are supported by this tutorial and you should be able to flash all files with no problems.
  • The tutorial will tell you to wipe data and factory reset the smartphone. This means that the system partition will be wiped in the process.
    – internal and external storage won’t be affected by this process.
  • Create Backup for all important files before starting the installation.
  • Enable the USB Debugging option from the Developer Options menu.
    – if the Developer Option section is not listed under Setting menu, then you should open About Phone, then scroll down to Build Number and tap seven times on it. The Developer Options will now appear and you can enable USB Debugging.
  • In the tutorial you’ll find two files, the ROM and the Samsung Addons one.
    – the ROM zip is the main file you need to flash and it doesn’t contain any of the Samsung bloatware.
    – the Samsung Add-ons file contains all Samsung bloatware.
    – KNOX Security is not bundled with the Add-ons zip, as KNOX security, when installed, will make it hard for you to root, flash recovery and other customizations.
  • Check the phone’s battery and make sure that its power charge level is over 50%. This will prevent the device from switching off in the middle of the updating process.
  • This post is for more advanced Android users, which is why it isn’t recommended for beginners to try and flash this firmware.
  • Note that we cannot be blamed in case you brick the phone or lose any data in the process.
  • In case you cannot complete the installation or you find a step that you’re not sure what it does, then you can ask for more help in comments. Make sure to leave a detailed comment so that we will be able to come up with a viable solution for whatever problem you might find in the process.

Read this entire tutorial and make sure not to skip any steps.

How to install Android 4.3 UCUEMJ6 Jelly Bean ROM for the Samsung Galaxy S4 AT&T I337:

  1. Download the ROM zip from here.
    – do not unzip the file.
  2. Optional download: Get the Samsung Addons (Bloatware) file from here.
    – don’t unzip.
  3. Connect your smartphone with your computer, then copy the downloaded content on your AT&T SGS4 internal storage.
    – disconnect the phone from PC when the files are copied successfully.
  4. Power off the device now.
  5. Boot the AT&T Galaxy S4 in custom Recovery Mode.
    – it can be done by pressing and holding Volume Up, Home and Power simultaneously.
    – release the buttons when the CWM or TWRP Recovery screen appears.
    – both CWM and TWRP are working with this tutorial.
  6. First, create a full NANDROID Backup for the ROM that is currently installed on your device:
    – CWM: select ‘backup and restore’, then save the file on your device’s internal storage.
    – TWRP: press Backup, then select the system files you wish to save. Confirm the backup.
    > this will set a restore point for your phone and it can be used in case something goes wrong with the updating process.
  7. Now, apply the Factory Reset:
    – CWM: select ‘wipe data/ factory reset’, then confirm.
    – TWRP: press Wipe, then ‘swipe to factory reset’.
    > if you don’t Factory Reset the phone, then it might not boot in normal mode with the new ROM.
  8. Next, install the Android 4.3 leaked ROM file on your AT&T Galaxy S4:
    – CWM: select ‘install zip from sdcard’, then ‘choose zip from sdcard’. Find the ROM zip and confirm its installation.
    – TWRP: press Install, then find the custom ROM zip. Confirm the process.
    > don’t press any buttons until all files are flashed with success.
  9. Users who want to flash the Samsung Bloatware zip, then can repeat step 8 action. Flash the other Addons zip file just like you did with the Rom file.
  10. After the installation is complete, then you can return to the main custom Recovery screen.
  11. Reboot your smartphone now.
    – note that the first boot process takes a while before all new files are loaded, which is why you shouldn’t press any buttons.
  12. Enter your Google Account details when the home screen of your device appears and take control over its new OS version.

These were all the steps that you had to take in order to successfully flash the leaked Android 4.3 ROM for your AT&T Samsung Galaxy S4 I337 smartphone. If you have any problems and you cannot complete the installation, then you can ask for more help in comments.

In case the device doesn’t go past the Samsung boot animation, it enters into a boot loop or the ROM doesn’t install for any other reason, then you should remove the phone’s battery. Re-insert the battery after a few seconds have passed and then you should repeat the entire tutorial once again. Try to flash both zip file or only the ROM, there might be some incompatibility issues between the two zip files, which is why you need to test more methods before managing to successfully install such leaked ROM.

If you don’t like the new ROM or the device’s performance is worse with Android 4.3 installed, then you can use the custom Recovery and restore the Galaxy S4 AT&T to its previous state using the files created in step 6. Also, more info about this release can be found in this XDA thread here.