Download Rooted G900AUCU4BOF2 Update for AT&T Galaxy S5

If you are looking for a more practical (root friendly?) way to update your AT&T Galaxy S5 to Android 5.0 Lollipop using latest G900AUCU4BOF2 firmware, then here it is. Thanks to awesome man known by the name of muniz_ri over at the XDA, here’s a zip file of the OF2 Lollipop update that is pre-rooted, and is flashable using the FlashFire android app. This may allow you to downgrade back to Android 4.4 too, while keeping root access on your device.

It’s not your ordinary ROM flash from CWM/TWRP recovery, and if you are using FlashFire for the first time, you need to exercise some caution. And for achieving root on AT&T S5 Lollipop OF2 firmware, you could easily do that, right? The ROM won’t flash the OF2 Lollipop update’s bootloader for obvious reasons — it’s because of that have to hack our way to OF2 root like this — but you will need bootloader of OA1 update for this for sure. Find the link and installation guide for it below, and better do this before flashing the pre-rooted Lollipop update. Lastly, this will keep your KNOX warranty flag intact, meaning you would not lose warranty because of this, unless you have already lost it if you used Chainfire.

By flashing this ROM, your AT&T Galaxy S5 will be updated to OF2 Lollipop firmware’s modem, non-hlos, kernel, system and stock recovery — that is, everything except the bad guy called bootloader. This helps in keeping root access, a must if you are used to it.

Requirements: To be able to keep root on AT&T Galaxy S5 on Lollipop update (OF2), you need root access for flashing this ROM. We will be using FlashFire app, which requires root. If you don’t have root access on your Android 4.4 firmware right now, get that first. You can install the 4.4 NCE firmware by downloading this file, and then flashing it using Odin (see help for Odin flashing here). NOTE that if your S5 is already updated to firmware ending with OC4 or OF2 (see build no. in About phone), then do not try to install OCE firmware, as downgrade is not possible from OC4 and and firmware. Once you have NCE, root your Galaxy S5 on it using TowelRoot. Just install the TowelRoot APK, and then open the app, and tap on the only button to get root access, without breaking warranty.

→ So, if you are already on OF2 or NC4 firmware without root, you cannot get root access now. While if you are on other firmware but don’t have root access, then you can go back to NCE firmware and then use TowelRoot to get root access.

Next, once you have root access, follow the guide below.

AT&T Galaxy S5 Android 5.0 Lollipop Update build OF2 with Root


Supported devices

  • AT&T SAMSUNG GALAXY S5, model no. SM-G900A
  • Don’t try on Galaxy S5 sets at Verizon, T-Mobile, Sprint, US Cellular or the Canadian, Korean and International variants.
  • Don’t try on any other device whatsoever


Warning: Warranty may be void of your device if you follow the procedures given on this page. You only are responsible for your device. We won’t be liable if any damage occurs to your device and/or its components.

Backup necessary stuff. Installing this ROM will wipe your device, so create a have backup of contacts, photos, videos and other files.

  1. Make sure you have root access. If not, read the second para above from the beginning to see how to get root access. Read the requirements para above to get help with root access on Android 4.4.
  2. If your current firmware is OA1, then ignore this step. Otherwise, flash the OA1 firmware’s bootloader as this is needed for pre-rooted OF2 lollipop update. For this, download this file, and then flash it using Odin using the guide here. Once you have root access and have updated the bootloader to that of OA1, proceed to flash pre-rooted Lollipop update on your Galaxy S5.
  3. It’s good to set the ‘Screen timeout’ to 10 minutes under Settings > Display.
  4. Download the ROM file, and transfer it to phone’s storage. Remember the location where you put it.
  5. Download the Flashfire android app that we will use to flash the ROM:
    1. Login into Google using the same Gmail ID that you are using on phone. Go to Google+ page and join the community.
    2. Next, sign up here to be able to install the app from play store and receive updates.
    3. Use the play store link provided thereafter to get to pay store page of the app and install it. It may take hours before it shows up for you in play store. You can only wait.
  6. Open the Flashfire app. Provide it root permissions by tapping on Grant button on the pop-up that shows up. (Tap on Agree on the Disclaimer pop-up that comes only one time. And read the Instructions section, it’s helpful.)
  7. Tap on + sign, select ‘Flash ZIP or OTA’ and then select the ROM file ( from step 3 here.flashfire-app
  8. On next screen, leave Auto-mount option unchecked, and just tap on checkmark sign at top right corner to continue.
  9. You will be back on main screen, tap on EverRoot. Make sure every option is unchecked. Then tap on the checkmark sign at right top corner to continue.
  10. Scroll down and tap on FLASH button. Tap on OK to confirm. That’s it. When done, device will reboot automatically. (Uh, don’t worry when Screen turns black and Flashfire does its things and pauses for around 1 minute in between. When rebooting, device will seem stuck at AT&T’s logo, for like 2 minutes, but will reboot all fine soon enough, don’t worry!)

Need more help with flashing the ROM using Flashfire app (steps 5 to 8 above)? Well, check this video. Works for every ROM on every Samsung phone when using Flashfire app.

Once Flashfire is done flashing the pre-rooted OF2 firmware based 100% stock ROM without any other customization than root, your AT&T Galaxy S5 will reboot automatically.

That’s it. Let us know if you know any help with this via comments section below. We’ll be sure to help you.

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Kapil still loves his Galaxy S2 i9100! No, really. And Galaxy Nexus! Need we say more what kind of guy he is? And he's also a die-hard Liverpool FC fan. Email:
  • Carlos

    Can I flash the prerooted ota with odin or with stock recovery by

    • The above file is to be flashed using Flashfire app only if you wanna keep root access.

      • tre killjoy

        can i flash this to an unlocked s5 that isnt rooted?

  • Muhaimin Mahzan

    My phone is booting very long and it still booting. It still shows the logo (powered by android) thingy. How to escape the boot?

    • If i’s been more than 20-25 minutes already, then do a factory reset. Remove battery, then place it back after 5 seconds. Then press and hold Power+Home+Volume Up button together until you see Samsung logo. Then you will enter 3e recovery.
      Do a factory reset from here. Move the selection using volume keys and use power button to select the wipe data/factory reset option.
      Then reboot the device, and it should restart fine.

  • Eddie

    Same thing happened to me! I’m devastated!
    Been trying everything to bring my phone back for hours.
    Tried the recovery mode thing but it doesn’t go into recovery. It flashes tiny blue letters for a second, saying recovery…but goes right back to
    “Could not do normal boot
    Odin Mode”
    Tried to put back old ROM but that doesn’t work.
    I really need help!

    • Krishna

      Was your device on Android 4.4 before you flashed the above Rooted firmware?
      Upon flashing, did you get PASS (black text in green background, in top left side in Odin?