Step 5. Open TowelRoot app.
Step 6. Click on “make it ra1n”. The app will root your phone and reboot in about 15 seconds.
Step 7. Let your phone reboot.
Step 8. Once rebooted, download and install SuperSU app from Play Store.
Step 9. Open the SuperSU app and when it asks you to update the SU binary, just hit “Cancel”. (Root works fine without updating.)
Step 10. When SuperSU app asks you to disable KNOX, press “OK”. This will get rid of KNOX, which is a useless security feature we don’t need and will only interfere with our root.
Step 11. To verify you have full root, install and open a rooted app such as Titanium Backup app.
You should see a Superuser request window like show below:
Congrats! You now have a fully rooted AT&T or Verizon Galaxy S5.
A: I cannot update the Superuser binaries!
Q: The SuperSU on the Play Store is not the latest version, download the latest version of SuperSU APK file here:
Then use My Files app to install it. You should be able to update binaries then.
Btw, binaries don’t affect root at all but SuperSU app won’t run without updating the binaries.