1. Install TriangleAway here. Thanks to Chainfire.
2. Open TriangleAway, reset flashing counter (you must have root access)
3. Download original unrooted firmware for T-Mobile Galaxy S3 (T999UVALEM) here. Thanks to SamMobile
4. Boot your phone into Download Mode (Volume down + power + home) and flash the firmware above via ODIN
5. If you have bootloop after flashing, remove battery, boot your phone into Recovery Mode by holding volume up + power + home (should be stock recovery because custom recovery will be lost), wipe data (factory reset) + wipe cache
6. When your phone finishes rebooting, you will see the GPS has been fixed and worked perfectly.
7. Upgrading to the latest JB 4.1.1 by flashing the rooted firmware by DocHoliday77 here. GPS still works.
Please thanks if this post is helpful.