[AT&T Samsung Galaxy S 5] Justin1198:
What You'll Need:

The experimental firmware: https://androidfilehost.com/?fid=745425885120704448 (Thanks @NavSad !)

My updated G900A RootPack: https://drive.google.com/file/d/1U7vwyq4T4609SiUQz43zLXvYOu9Hqohb/view?usp=sharing

(Windows Defender may detect TowelRoot as an Android Malware Exploit, you may need to disable defender temporarily.)

If you want to downgrade to NCE/KitKat: The G900A_NCE.Zip file: https://drive.google.com/file/d/1ahpVGnG3bQ-mEoztN4XUvdbTOW64IdoT/view?usp=sharing

Get Ready:

You will need to extract the RootPack files and move the RootPack folder along with the G900A_Firmware.zip to an external SD and put it in your phone.

What To Do:

Step 1: Go back down!

Download the experimental firmware and extract the zip on your computer.

Open Odin3, select the AP slot, and specify the experimental firmware so you can flash it.

Under Options, Make sure only "AutoReboot" and "F. Time Reset" are selected.

FLASH

Step 2: Our Old Friend

After the OS is installed, go to the file manager and install Flashfire, SuperSU, TowelRoot, BusyBox, and SafeStrap.

Run towelroot. Simply hit "make it ra1n" and 3 seconds later you'll have the root binaries installed.

Now open the SuperSU app and hit "continue", let it do its thing and then update the SU binaries (you don't have to reboot)

Step 3. Where to go?

You now need to determine where you want to go?

You can downgrade to NCE or upgrade to OF3

NCE DOWNGRADE/ROOT GUIDE

(KitKat) (Will downgrade you to KitKat and root it)

Now open BusyBox, dismiss the social prompt, and hit install

Now open SafeStrap Installer, grant SU Permissions, and Install recovery (

DO NOT Reboot into it

)

Open FlashFire, Grant SU Permission, and Accept the Disclaimer.

Hit the '+' and hit 'Flash Firmware Package', navigate and select the G900A_NCE.Zip, and let it scan the archive.

Check

Recovery, System, Cache, and Persist.

Uncheck

modem/Firmware

Hit the Check in the Top Right to confirm changes and Hit the '+' again

Select Wipe System. 3rd Party Apps, Cache Partition, Cache Partition Format, and select the check in the top right to confirm changes

Drag wipe above the flash firmware package

Select EverRoot,

Uncheck

"Inject SuperSU" (If you don't, it will cause a

kernel panic

)

Select Reboot,

Check

Select "Preserve Recovery", and select the check in the top right to confirm changes (If you don't do this, you won't have recovery once you downgrade.)

HIT FLASH

and OK (This will work, don't panic) It may take up to five minutes for the process to complete, if it fails, reflash combination.

After the OS is installed, go to the file manager and install TowelRoot, SuperSU, BusyBox, And SafeStrap

Run towelroot. Simply hit "make it ra1n" and 3 seconds later you'll have the root binaries installed.

Reboot to make SuperSU detect root.

Now open the SuperSU app and hit "continue", let it do its thing and then update the SU binaries (Yes, Reboot now)

Now open BusyBox, grant SU Permissions, dismiss the inital message and install busybox

Now open SafeStrap, grant SU Permissions, Install Recovery.

Your all set.

OF3 UP/DOWNGRADE/ROOT GUIDE

(Lollipop) (Will downgrade you to Lollipop and root it)

Open FlashFire, Grant SU Permission, and Accept the Disclaimer.

Select "Flash Zip/OTA" and Select the G900A_OF3.zip

Mount /system read/write

Select "Flash Zip/OTA" and Select the G900A_OF3_Tether.zip

Mount /system read/write

Select Wipe System. 3rd Party Apps, Cache Partition, Cache Partition Format, and select the check in the top right to confirm changes

Drag wipe above the flash firmware package (This will fix battery/heating/lag issues while your on OF3) (Trust Me)

Select Wipe System. 3rd Party Apps, Cache Partition, Cache Partition Format, and select the check in the top right to confirm changes

Drag below the G900A_OF3.zip (This will clean up the setup) (Trust me)

Hit "flash", let it flash, reboot, and load.

HIT FLASH

and OK

After OS is installed, you will have root.

Copy G900A_OF3_Kernel.zip to the RootPack folder.

Install BusyBox, open and grant SU, Install BusyBox

Install SafeStrap, open and grant SU, Install to Recovery. (

DO NOT Reboot into it

)

Download the NCE_Flasher then install it, and open it up then hit " flash", wait for it to finish then hit "tap to reboot" and it will take you directly to SS recovery. Then you can flash whatever MODs or addons you wish or even ANOTHER ROM, just make sure you wipe everything but the external SD card if you are flashing a new ROM and you should be good.

Remember to ReFlash the G900A_OF3_Kernel.zip file in SafeStrap before you exit SafeStrap otherwise you will not be able to reboot.

If you forget and end up with an error, Just flash G900A_OF3_Kernel.zip with Odin3. (It won't wipe anything)

Marshmallow

---Working on a method---

(Won't stop until I have every update rooted.)

Marshmallow is currently unrootable on the G900A and G900V (CID 11). A method will likely appear in the future.

It is safe for you to flash to the latest Marshmallow, you will be able to restore the experimental combination to root again.

Notes: This guide is an updated version of AptLogic's Guide. ( Can a mod please sticky that thread :confused: )

I have created this thread as an "elimination of confusion"/"Catch All" and I will update the thread once I get root on Marshmallow , https://xdaforums.com/att-galaxy-s5/general/guide-merry-christmas-heres-t3516196.

Thank you to AptLogic and everyone involved in the development of root for this device.​