For those of you with a rooted AT&T Galaxy S5 and still have not updated to Lollipop, here’s how you can easily update to Android 5.0 Lollipop and also keep root. This method is preferred over flashing stock firmware as you will be able to keep root.
First, you will need to download FlashFire. To do that, first sign up for Android FlashFire G+ Community, then sign up for the beta FlashFire here. Once you do those two, open up this link with your Play Store app and you should be able to install FlashFire app.
*NOTE – This method will factory rest your device so MAKE A BACKUP of apps and SMS before preceding! (You can use Titanium Backup app for apps and SMS Backup app for SMS.) But it does not erase your personal files, photos, and videos.
Next, open up FlashFire app. If the FlashFire app doesn’t open, disable auto date/time and change your system year to 2013 (this is a bug in the app). Then it should open.
Next, hit the plus button.
Then choose, “Flash ZIP or OTA”.
Then choose the Lollipop stock firmware with root you downloaded earlier.