Update T-Mobile Galaxy S3 SGH-T999 with CM10 Android 4.1.1 Jelly Bean Firmware

• Last modified: Tips

After the international version and the AT&T Galaxy S3, T-Mobile has also got the CM10 Jelly Bean custom ROM released. Remember, this is not an official ROM and since CM10 is in early stages, it might have a number of bugs in it.

Installing CyanogenMod 10 (CM10) Android 4.1.1 is just like flashing any other custom ROM on your T-Mobile SGS3. In this tutorial, we will guide you through the process of how to install CM10 on Galaxy S3 SGH-T999 with complete steps. There are lots of known issues in this ROM, but they are expected to be fixed very soon as further builds are released.

Samsung Galaxy S III GT-I9300

Disclaimer: All the tools, mods or ROMs mentioned below belong to their respective owners/developers. We (TeamAndroid.com) or the developers are not to be held responsible if you damage or brick your device. We don’t have you on gun point to try out this tutorial ;-)

Known Issues in CM10 on SGS3:

  • Overlay for UI (extra butter)- We’re waiting on CodeAurora to publish, UI is a little janky.
  • A2DP is completely broken
  • Picasa sync doesn’t work (if you overwrite the Gallery with the Google version, you’ll break the camera, don’t do it)
  • All the things.

Make sure you have installed all your USB drivers for the T-Mobile Samsung Galaxy S III to connect it with the computer. Download Samsung Galaxy S3 USB drivers! Apart from just the USB drivers, there are a few more things that you need to take care of.

1. You need to enable USB debugging mode. This helps to connect your Android phone with the PC. See here: How to Enable USB Debugging.

2. Your phone battery should be 80-85% charged. If your phone goes off suddenly because of battery, during flashing ROMs or installing mods and updates — your phone might go dead permanently. See here: How to Check Battery Percentage.

3. Backup all your important data that you might need as soon as your flash a new ROM, or make a backup for just in case, you never know when anything might go wrong. See below on how to backup data:

Data can also be backed up using Samsung KIES for their devices, but if you backup data manually, you get more options what top choose from and it is very easy to move data across Android devices from different manufacturers, i.e moving Samsung Galaxy Note backup data to HTC One X.

4. Your phone should be factory unlocked. Additional instructions for locked Android devices will be added in the tutorial for unlocking devices.

Now, let’s proceed with the tutorial on the next page and install CM10 on Galaxy S3 SGH-T999.