[AT&T Samsung Galaxy S 5] wwit:
Install Rooted Lollipop on AT&T Galaxy S5 (if your handset is pre lollipop)

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

Preparations

-You must have a rooted AT&T Galaxy S5.

-Make sure you have installed Safestrap recovery on your device.

-Enable USB Debugging on your Galaxy S5.

-Download Odin v3.09.

-Download the rooted Lollipop backup file: G900A_OC4_Stock_Rooted_Backup.rar.

-Download Lollipop stock partitions: G900A_OC4_Stock_Partitions_wOA1_BL.tar.md5.

Instructions

Rooting your device requires Towelroot which can be downloaded from google via your handset browser.

Install Busybox and SuperSU.

Open Safestrap recovery, Backup the data partition (if you want to keep everything that's setup on the handset). Restart the handset.

On your desktop or laptop extract G900A_OC4_Stock_Rooted_Backup.rar file.

Copy the extracted folder to ext-sdcard/TWRP/BACKUPS/xxxxxx folder on your handset (the folder name varies from device to device).

Open Safestrap recovery again (restarts the handset into Safestrap recovery), Wipe> Advanced Wipe and wipe everything except the ext-sdcard and the data partition.

Now go back to the main menu in Safestrap recovery, tap the Restore option and restore G900A_OC4_Stock_Rooted_Backup.

This will get your handset to 5.0. If you want your data (ie how you configured your device before starting the upgrade process, restore the data partition in Safestrap before moving onto the next step. If you don't want your data restoring miss this step out).

Select Reboot> Download mode option (this is an option within Safestrap).

Connect your S5 to PC using the original USB cable and launch Odin.

Make sure you see “Added!!” text in the message box on Odin. It indicates that your device has been detected by Odin.

Now click the AP button on Odin and select G900A_OC4_Stock_Partitions_wOA1_BL.tar.md5.

Finally, click the Start button to initiate installation.

When the stock Lollipop partitions file is flashed, your S5 will reboot automatically.

Just wait until your phone boots up. It might take a while so wait patiently. You can now enjoy rooted Lollipop on your AT&T Galaxy S5

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Search the forum or google for the two files mentioned above, this is what I did to find them (at least do something yourself - it's how you learn :)

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This works. I can confirm I have corrupted my handset over 5 times in one evening trying to get from stock 4.4.2 up to 5.0 and I was able to do it. Once more I was able to restore all my data from 4.4.2 into 5.0 which kept all my settings, installed apps, phone contacts, calendar - everything basically. It's very interesting how the android structure works, forget how Windows works.. The data partition holds all your customised settings for the handset and I mean everything.. apps, contacts, calendar entries, installed apps, lock screen, call logs, messages.. etc. The best way to save your data is to use Safestrap on 4.4.2 and backup the data partition which will store it in the TWRP folder on your SD card. When you come to restore 5.0 file, before rebooting the handset, restore the data partition and you will have Lollipop installed as well as all your data that was on the handset before you started the upgrade. It's amazing, no having to setting up the handset again, configuring things, downloading from the store.

As one final test I crashed the OS on the handset (what some people like to call soft brick - which isn't the actually meaning of bricking - more later on that). I then used safestrap to restore the lollipop files, restored the data partition from my TWRP backup (on the SD card) and then moved on to the odin partition restore stage and listed above - bingo everything thing was back to lollipop 5 with all my data.

FYI - the true meaning of a bricked device is a device that cannot be put into download mode. If you can get into the download mode (pull battery, insert battery, press the vol down and home button whilst powering on) you can recover the handset.. that 100%

I even managed to get the handset into a state that said contact your nearest AT&T store for help - this is enough to make anybody think your handset is truely screwed.. WRONG, again, if you are able to get into download mode then you can recover the handset without taking it back to AT&T.

I'm willing to help anybody with a phone that is able to get into download mode, simply because I know it can be recovered.

I took the time to read through this excellent forum and all the answers are here if you take the time to search and then read the guides.

*** the process described above was extracted from a post by Muniz_ri - I've posted the extracted process to show the process I used. I cannot take thanks for the work provided by another member ***