I tried this and it worked!. In order for it to work, you have to flash an ND3 kernel and use towel root then go back to an NG3 kernel. Follow this guide. [How-To] Root G900AUCU2ANG3 | AT&T Samsung Galaxy S 5 | XDA Forums
(Note: On step 4 in this tutorial I recommend you use towelroot reboot and use towelroot again multiple times. Root Checker may say you don't have root when you really do. So test your root on other root apps such as cputemp or battery stats plus or disable service or any other app that uses root before moving to step 5).