Install Android 5.0 Lollipop Firmware on AT&T Galaxy S5 SM-G900A (OC4)


Android Lollipop is undoubtedly the best iteration the OS has seen so far. It was released in November last year and has reached most devices that had been released during the last couple of years. While Samsung devices usually get new software update pretty late, the Lollipop update came to the flagship phones by the OEM quite sooner than expected.

The AT&T Galaxy S5 received the Lollipop OTA back in March. Most of the owners have already been enjoying the sweet treat for months now. Since the Lollipop update for the AT&T S5 brings undowngradable bootloader and there is no working root exploit available for the device, many users thought it better not to take the OTA right away.

If you have been with for a while, you might remember us sharing XDA member muniz_ri’s workaround for installing the rooted Lollipop ROM on the AT&T Galaxy S5 without upgrading the bootloader. The method requires root privilege on the device and involves flashing the ROM using Chainfire’s FlashFire app. In the same tutorial, we also shared the Lollipop OTA zip file that can be flashed manually via stock recovery. The method, however, demands the Android 4.4.4 firmware as a base to install the OTA.

Anyway, if you have not been able to update your AT&T Galaxy S5 SM-G900A with Lollipop for some reason, it’s time for you to enjoy Lollipop by installing the stock firmware manually. Better late than never, eh! Since network providers like Verizon and AT&T don’t release firmware for their devices for public download, it’s availability of the Android 5.0 stock firmware with build version G900AUCU3BOC4 might prove a lifesaver of many users of the phone. Thanks to numatron from XDA forums for repackaging the firmware as an executable one-click file.

Getting Prepared

  • Download the stock Lollipop OC4 firmware for the AT&T S5:  |  Mirror
  • Enable USB Debugging on your Galaxy S5 by going to Settings> Developer options. If you do not find the option under device settings, refer to our detailed tutorial on enabling it.
  • Download and install Samsung USB Drivers or Kies on your computer. Skip this step if you already of any of them installed.
  • The firmware installation won’t wipe your phone’s app or data but we still recommend backing up your data as a precaution.
  • Lastly, make sure your device has ample battery juice (60% at least) before proceeding.

Installing Lollipop Firmware on AT&T Galaxy S5

  1. Having downloaded the file, extract it using a Zip extractor program.
  2. Now reboot your Galaxy S5 into the Download Mode: turn off the device, press and hold the Volume Down + Home + Power buttons at the same time for 2-3 seconds. When you see the warning screen, press the Volume Up key.
  3. Now connect your phone to the computer using a compatible USB cable.
  4. Now click the one-click EXE file.
  5. When Odin is launched, just click the Start button to initiate firmware installation.
  6. Wait until the installation is finished and then your phone will reboot automatically.

Done! In case your device is stuck on the AT&T splash screen for more than 5 minutes, pull out the back cover and phone’s battery, place it back after 20-30 seconds and then perform a data/factory reset via stock recovery. You can stepwise instructions for resetting your phone here. You can now enjoy fully stock Android 5.0 (OC4) firmware on your AT&T Galaxy S5 SM-G900A.


  • Derek

    Stuck on the ATT splash screen. Did the factory reset and it still stops there.

  • Caleb Crawford

    Yes, it does. I tried it and it worked first try.

  • hmir

    Will this method work for the Galaxy S5 G900A with kitkat 4.4.2?

  • Since the Marshmallow firmware for the device is not available for download, you’ll have to flash OTA zips in correct order to get Marshmallow. Look for the OTA Zips and flash them one after another in the following order:

  • usman amjad

    G900A_Downgrade_to_NCE fail error

  • Kumar

    How to update S5 G900A android 5.0 ucu3boc4 lollipop to 6.0 marshmallow

  • Kumar

    How to update S5 G900A android 5.0 ucu3boc4 lollipop to marshmallow

  • Redownload the file.

  • Singh Manjit

    MD5 hash value is invalid

  • Hermes00

    Thanks very Much Rakesh!! It works fantastic!! From 4.4.2 to 5.0, no problems at all. And with tethering working too 😉 (From Buenos Aries, Argentina, very grateful!)

  • Mo

    Any other 1 click update doctor Rakesh ?

  • rapheal asamoah gyan

    When i click the download link it says file does not exist, could you please send me a new link? Thanks

  • Hamid got Hella Bitches

    Great guide, much thanks! My phone even got stuck during the at&t splash screen as you said and I had to take out the battery to reboot it.

    Now i wonder… is there at one-click file like this for the 5.1.1 firmware for the SM-G900A?

  • Chulo Wolfenation

    my phone does not read through usb when I’m in reboot mode

  • Ryan Dang

    i got trouble. when i extract the file them ask me the password, so what is the password

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