[AT&T Samsung Galaxy S 5] muniz_ri:
**Make certain that your reactivation lock in security settings is off before beginning this process**

1. Take the OA1 OTA update.

2. Download and install Towelroot-v3.apk(this version does not require internet access).

3. Place your phone into "Download Mode" (press and hold the Home, Volume Down, and Power keys until the phone powers on and displays warning screen, then press Volume Up key) and flash the G900A_ND3_Stock_Kernel using Odin's PDA slot(AP in Odin v3.09+).

4. Open the Towelroot app from your app drawer and press "Make it Rain" to root your device.

5. Power off then boot into "Download Mode" again and flash the G900A_OA1_Stock_Kernel also using Odin's PDA slot(AP in Odin v3.09+).

6. Install SuperSU to manage root access. Done!

Changelog: http://www.att.com/esupport/article.jsp?sid=KB424848&cv=820&_requestid=1642069

Troubleshooting:

1. Should the OA1 ota update fail consider returning to factory stock NCE (all User Data will be lost) by flashing the G900A_Downgrade_to_NCE.tar using Odin's PDA slot(AP in Odin v3.09+) then taking the OTA updates to OA1. Or, place the G900A_NCE_to_NG3_OTA.zip and G900A_NG3_to_OA1_OTA.zip onto your ext-sdcard and sideload from stock recovery starting with the G900A_NCE_to_NG3_OTA.zip. Once updated to OA1 continue from Step 2 above.

2. When flashing the kernel the most common cause of an Odin flash failure is a bad usb port or cable. Please check before reporting a failure!

Notes:

1. The above process will not affect your User Data or Knox Warranty Flag.

2. After flashing the ND3 kernel your phone will run a little wonky and towelroot may not root on the first try. If that happens reboot and try towelroot once again. Once rooted and after flashing the OA1 kernel your phone will once again run like a champ!

Alternative Safestrap Method:

1. Place the G900A_OA1_100%_Stock_Rooted_ROM onto your ext-sdcard.

2. From Safestrap recovery press "Backup" and backup your User Data.

3. From the main menu press "Wipe" then perform an "Advanced Wipe" and wipe everything but your ext-sdcard.

4. Next, press "Install," then select and install the G900A_OA1_100%_Stock_Rooted_ROM.

5. Once complete, press "Restore" and restore your User Data.

6. Last, from the main menu press "Reboot," then "System." Done!

After following the above process your phone will pause on the AT&T splash screen for about 2 minutes before rebooting.

Optional - Enable Native Tethering AddOn:

1. Place the G900A_OA1_TetherAddOn.zip onto your external sd-card.

2. From Safestrap recovery flash the file using "Stock" Slot but do not wipe!

3. Reboot. Done!

Notes:

1. The above process will not affect your User Data or Knox Warranty Flag.

2. This process will update your Modem, Non-hlos, System, Kernel, Stock Recovery, and Bootloader to OA1 (BusyBox is also pre-installed).

3. The User Data "Backup" and "Restore" steps in the instructions are not mandatory but will greatly reduce your device's set-up time. All currently installed non-system apps and settings will be automatically restored.

Credits:

benwaffle - for his flashboot script allowing flashing of the OA1 kernel(built into the ROM) in Safestrap.