As you already know, the AT&T Galaxy S3 device has received a leaked Android 4.3 build. Now, the same leaked ROM has been ported for the Samsung Galaxy S3 T999, which is why you should use this tutorial if you want to learn how to flash it successfully.
The Android 4.3 UCUEMJ2 ported firmware for TMO Galaxy S3 is pre-rooted and KNOX has been removed completely from it. Before starting the installation you will need to take a look at the guidelines below:
- Use this tutorial only for the Samsung Galaxy S3 T-Mobile model number T999.
- don’t try to flash the files you find here on any other Android devices, as you will end up bricking it.
- Your TMO Galaxy S3 has to be rooted and running a custom Recovery image like CWM or TWRP.
- Factory Reset is mandatory, which is why you need to know that all data stored on your device’s system partition will be removed in the process.
- It is highly important that you create a full NANDROID Backup of your current ROM before starting the installation.
- this step can be found in the tutorial part too.
- If you want to backup data from installed apps, then you can use the following tool for Android: Helium (here).
- If you want to backup SMS, Call Logs info or APN Internet Settings, then you can use these apps: SMS backup & restore | Call Logs backup & restore | APN Settings Backup & Restore. Root access is needed for some of these apps.
- Sync your Contacts info with your Gmail account.
- Enable USB Debugging for your device from Developer Options menu.
- This is a guide for advanced Android users. You cannot blame us in case you brick your device or lose any important data in the process.
- Read the entire post and make sure not to skip any steps that I’ve listed below.
- If you cannot complete the tutorial then you can ask for more help in comments.
- Make sure that the phone’s battery has enough power left in it before it doesn’t switch off. If the phone does power off then you will be forced to repeat the entire tutorial once again.
How to flash Ported & Rooted Android 4.3 UCUEMJ2 firmware for T-Mobile Samsung Galaxy S3 T999:
- Download the StockMOD ROM zip from here.
- Download the TMO Galaxy S3 Modem zip from here.
- Download Kernel and Root Fix zip from here.
- Connect your TMO Galaxy S3 with your computer via USB Cable.
- Move all three zip files on your phone’s internal storage.
- don’t unzip the files.
- Disconnect the phone from PC when the files are copied.
- Power off the Galaxy S3.
- Boot the SGS3 in custom Recovery Mode:
- if you don’t know how to do it, then you can learn using the info here.
- note that both CWM and TWRP are supported by this guide.
- Now, create the NANDROID Backup for the currently installed ROM:
- CWM: use the ‘backup and restore’ option. Save the file on your phone and then continue to the next step.
- TWRP: press Backup, name the file and swipe to confirm process.
> this sets a restore point for your phone.
- Next, apply the Factory Reset for your smartphone:
- CWM: select ‘wipe data/ factory reset’. Confirm the process.
- TWRP: press Wipe, then swipe to factory reset.
- Now you can flash the StockMOD ROM file:
- CWM: Select ‘install zip from sdcard’, then select ‘choose zip from sdcard’. Find the zip file and confirm the installation.
- TWRP: press Install, then find the ROM zip. Confirm the installation by swiping the blue button at the bottom of the screen.
- After the ROM is installed, repeat step 11 and flash the Galaxy S3 Modem zip file.
- After the ROM and the Modem files are installed, repeat step 11 actions and flash Kernel and Root Fix zip file.
- When all three files are installed, return to the main recovery screen and reboot your device in normal mode.
- Enter your Google Account details and take control over your device once again.
These were the steps you had to take in order to complete the updating process for your T-Mobile Galaxy S3 device.
Note that the first boot process of your new ROM takes a while to complete, which is why you shouldn’t press any buttons until all files are loaded. In case the device has difficulties loading all files, then you should power off the device and then repeat the entire tutorial once again.
If you don’t like this new ROM, then you should use the NANDROID Backup files created in step 9 and restore your device to its previous state.
If you have any other questions, then use the comments field below.