You can now install Android 4.2.2 on T-Mobile Galaxy S3 I999 thanks to the official CM10.1 custom ROM. The first nightly of CyanogenMod 4.2.2 Android ROM for T999 smartphones has become available for download. So, users with rooted devices who have a custom recovery installed can now flash CM10.1 JB 4.2.2 ROM on T-Mobile Galaxy S3 SGH-T999.
What you need:
- Rooted T-Mobile Galaxy S3 T999
- ClockworkMod (CWM) or TWRP Recovery installed on your device
- USB debugging enabled on your phone
To install this ROM update, all you have to do is to:
Step 1: Download latest CyanogenMod Android 4.2.2 Nightly: cm-10.1-20130217-NIGHTLY-d2tmo.zip
Step 2: Download GApps for CyanogenMod ROM
Step 3: Copy the ROM and GApps files on root of device’s SD card
Step 4: Flash both the files one by one
Step 5: Reboot your device
After your device boots up, you will have CyanogenMod (CM) 10.1 Android Jelly Bean 4.2.2 on T-Mobile Galaxy S3 SGH-T999.
For those who need a detailed guide, head over to this link: How to install custom ROM using CWM Recovery.