[Galaxy S 5 Q&A, Help & Troubleshooting] Terry.nicolau:
Hey guys,

So I am a relative NOOB - I flashed my girlfriend last phone, ZTE Blade 2 and loaded a custom ROM made from a guy in Brazil that actually worked really well off the paltry 4GB storage it had. Eventually got it to read the 8GB SD card as internal memory - but this was 3 months ago and involved a lot of trial and error before figuring it out - thanks to XDA of course.

So I bought her a new S5 sealed form Korea - SM-G900A AT&T version.

Firmware version: 4.4.2.

I tried to run an OTA update to Lollipop and said it couldn't find anything

Then I realized it was rooted, and I thought maybe that is what is preventing the OTA update. So yesterday I unrooted the phone and loaded STOCK Samsung from:

http://xdaforums.com/showthread.php?t=2785363

Ran the OTA update request, still nothing.

Thinking as its an AT&T phone it may not run the OTA update on my countries networks - South Africa.

Thinking 2 stratergies going forward:

1 - Download the OTA Lollipop 5.1.1 version and forcing it to update without rooting the phone.

As described here:

http://www.droidviews.com/install-rooted-lollipop-on-att-galaxy-s5-sm-g900a/

Problem is I don't trust other sites and had good experiences with XDA so if someone could provide me a link to a XDA thread that hosts an OTA Lollipop update I would appreciate it.

Install Lollipop OTA on AT&T Galaxy S5

Make sure your AT&T Galaxy S5 is 100% stock Android 4.4.4 KitKat firmware.

Now download the Lollipop OTA package: OTA_S5_5.0.zip | Mirror

Copy the OTA zip file to the external SD card of your phone.

Enable USB Debugging on your phone as precaution.

Now turn off your device and reboot into the stock recovery. To do so, hold the Volume Up+Home+Power keys together while the device is switched off. As soon as you see the Samsung logo, release the Power key and keep the other two keys pressed until you see the recovery menu.

Using the volume keys, scroll to apply update from external storage option and select it by pressing the Power key.AT&T-Galaxy-S5-stock-recovery

Navigate to the OTA update Zip package and select it.

Confirm installation when prompted.

When the file is flashed, go back to the main menu and select “reboot system now” option.

2 - Rooting the phone and upgrading the ROM to Lollipop.

As described below - problem is I don't want to void the warranty (could be void considering was rooted when received) nor brick the phone.

I prefer lower risk option UNLESS someone has a secure method of doing it? Any advice appreciated

Install Pre-Rooted Lollipop on AT&T Galaxy S5

If you want to enjoy root privilege on your AT&T Galaxy S5 running Android 5.0 Lollipop firmware, the following instructions would help you do that.

Warning!

You can use this method regardless of what firmware or build version your phone has. However, you must be rooted to be able to use the FireFlash app! Flashing the pre-rooted firmware provided below will not trip the KNOX Warranty Void flag. The procedure given below is considered risky. Follow it on your responsibility!

Preparations

To gain root access on your AT&T Galaxy S5 running KitKat, you can try Towelroot.

Enable USB Debugging on your Galaxy S5. This step has nothing to do with the method given below but it could be a lifesaver if anything goes wrong.

Install Chainfire’s FireFlash app on your AT&T Galaxy S5. Since this new app is only available for beta-testers currently, go to the Google+ page and join the Android-FlashFire community. You must be signed into Google+ using the same Gmail ID that you use on the Google Play Store. Having joined the community, click the Play Store link to download FireFlash Beta app.

Download the stock rooted Lollipop firmware for the AT&T S5: G900A_OC4_Stock_Rooted_ROM_wOA1_BL.zip (Note: The ROM is currently not available.)

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Please advise on the best way going forward. I have about 3GB left on my data to play with so the next ROM I download I want to be my last.