However it's a nightly build ROM, thus expect some bugs and there are features that don't work.
If you want to install CM10.2 ROM Jelly Bean 4.3 on T-Mobile Galaxy S3 then you can follow the instructions below. But please read the following first.
- Backup the Android data.
- Enable Android USB debugging mode first.
- Root your device with a ClockWorkMod recovery installed.
- Remember you are the one should be held responsible for any result following the instructions on this post.
Install Android 4.3 CM10.2 ROM on T-Mobile Galaxy S3 SGH-T999
Step 1 -Download CM10.2 ROM Jelly Bean build and download Google apps to your computer and store it in the place you can easily find like Desktop for example. (see apps for Android)
Step 2 -Now plug your smartphone to the PC of yours using a USB cable.
Step 3 -Then copy this Android 4.3 ROM and Google Apps zip and paste it to your SD card. Place the files in the SD card root.
Step 4 -Now shut down your phone, then unplug your device from USB.
Step 5 -It is time to enter the Recovery mode. Simply turn your device ON at the same time, press and hold these buttons simultaneously: Volume Up + Home + Power.
Step 6-And within the ClockworkMod recovery, do a full data wipe first. Then find this “install / install zip from SD card” then click and hold the Power button to select it.
Step 7 -Again press Power then choose “choose zip from sdcard”.
Step 8 -Use the volume keys to go to the Android 4.3 zip you pasted to SD card, then choose it using the Power button. Then on the next screen confirm the installation for it to begin. (Do from step 1 to step 8 again to install Google Apps).
Step 9 -Once the installation is completed, head to “+++++Go Back”. Then reboot your device, by choosing the “reboot system now” on the recovery. Your device will take reboot, this process may take few minutes, therefore just wait.