As you might already have heard (and even tried out), two official Jelly Bean Android 4.1 OTA updates have been leaked for the T-Mobile Galaxy S3, the latest being the UVDLI3 firmware. XDA Senior Member djintrigue808 has taken this UVDLI3 OTA update and made a custom ROM out of it, called JBFrost.

JBFrost is essentially the same UVDLI3 Jelly Bean ROM leaked for the device, but has been modified to be installable as a custom ROM. It is also rooted, and has been stripped of all T-Mobile bloatware as well. Those looking for an easy way to try out the official Jelly Bean firmware, removed and free of bloatware, can try out JBFrost ROM by following the guide below to install it. Keep in mind that the ROM is based on a pre-release firmware, so there may be some issues and some things might not work properly.

Now, let’s see how the JBFrost ROM can be installed on the T-Mobile Galaxy S3.

Compatibility

This hack and the guide below are compatible only and only with the T-Mobile Galaxy S3, model number T999. It’s not compatible with other US variants or other devices. Check your device’s model number in Settings » About phone.

Warning!

The methods and procedures discussed here are considered risky and you should not attempt anything if you don’t know completely what it is. If any damage occurs to your device, we won’t be held liable.

How to Install JBFrost UVDLI3 Jelly Bean ROM on T-Mobile Galaxy S3

  1. This procedure will wipe all your apps, data and settings (but it will NOT touch your SD cards, so don’t worry about those). Backup your Apps and important data — bookmarks, contacts, SMS, APNs (internet settings), etc. This Android backup guide would help you.
    NOTE: Don’t forget to at least note down your network’s APN settings, which are required to make mobile data work. Go into Settings » More » Mobile Networks, click on the APN that is in use, then note down the setting for each field. While APN settings should be automatically restored from network, you can enter them manually if needed to make mobile data work. You can also find your APN details → here.
  2. Install ClockworkMod recovery on your phone by following the guide → here. Skip this step if you already have ClockworkMod recovery installed.
  3. Download the latest version of the ROM from the source page.
  4. Copy the ROM file to the internal SD card. Do not extract them.
  5. Now, boot into ClockworkMod recovery. To do that, turn off your phone. Then, hold down Volume Up, Home and then the Power buttons together until the screen turns on, then let them go. The phone will boot into ClockworkMod recovery in a few seconds.
    In recovery, use the volume buttons to scroll up/down and the home button to select an option.
  6. Perform a Nandroid Backup of your existing ROM, so that you can always restore it from recovery if something does not work out with this ROM. To perform a backup, select Backup and Restore –> On the next screen, select Backup again. Go back to main recovery menu after backup is complete.
  7. Select wipe data/factory reset, then select Yes on next screen to confirm. Wait a while till the data wipe is complete.
  8. Select install zip from sdcard, then select choose zip from sdcard. Scroll to the ROM file on the SD card and select it. Confirm installation by selecting Yes – Install _____.zip on the next screen. The ROM will start installing.
  9. After the ROM finishes installing, select go back then select reboot system now to reboot the phone into the JBFrost Android 4.1.1 ROM.

NOTE: To go back to your previous ROM if needed, boot into recovery (as given in step 5), select backup and restore then restore your previous ROM by selecting it from the list.

The Android 4.1 Jelly Bean based UVDLI3 ROM is now installed and running on your T-Mobile Galaxy S3. Visit the official development page for more info and to get the latest updates on the ROM. Share your thoughts on the ROM in the comments.