Update G900AUCS4DQC1 stock Marshmallow on AT&T S5 G900A [March security patch]

AT&T is on the roll and delivering monthly security updates to it’s devices. Samsung Galaxy S5 bonded with AT&T is receiving an update carrying March security update along multiple performance improvements in over all firmware. The AT&T S5 G900A update is based on Android 6.0.1 Marshmallow, carrying build number G900AUCS4DQC1 and weighs 20MB. The update is rolling out via OTA but you can flash it on your device manually by following the two other methods including Kies and Odin. If your device is un-rooted then head towards Settings > About phone > Software updates. Check for the new firmware if available.

Below we have also mentioned the process to flash G900AUCS4DQC1 update on AT&T S5 G900A via Kies or Odin if you are unable to get update via OTA. We have already posted similar guide along same process for Samsung’s latest flagships because it has nothing to do with the change build number or Android version, all you need is an Odin tool along the firmware tar and a PC with latest Samsung USB drivers installed on it.

Firmware details:

Device Name: Samsung Galaxy S5 [AT&T]

Model: SM-G900A

Version: Android 6.0.1 Marshmallow

Build Number: MMB29M.G900AUCS4DQC1

Android Security Patch Level (SPL): March 1, 2017

Size: 20MB

Manually update G900AUCS4DQC1 firmware on AT&T S5 G900A

Disclaimer: Follow the guide on your own risk, the writer would not be responsible if you damage your device during the firmware installation process nor we are forcing you to perform the flashing process. Don’t proceed if you can’t follow the instructions carefully.

Process to update G900AUCS4DQC1 firmware on AT&T S5 G900A via Kies

If you remain unsuccessful in updating your device via OTA then visit the link below to update it via Kies.

Update G900AUCS4DQC1 firmware on AT&T S5 G900A via Samsung Kies

Hope this process helped you, still if you find problem with it then follow the guide below to update it manually via Odin tool.

Process to update G900AUCS4DQC1 firmware on AT&T S5 G900A via Odin


Your device should be charged 70% at minimum to avoid shutting down during the process.

Enable USB Debugging. Go to Settings > Developer Options > Enable USB debugging

Download and extract Odin 3.12.3 from here

Process to update firmware via Odin.

Now turn off your device completely.

it’s the time to boot your device into ‘Download Mode’, to do so follow this guide

Once in download Mode, follow this guide to update the firmware via Odin.


Download the stock Android 6.0.1 Marshmallow G900AUCS4DQC1 tar firmware for AT&T S5 G900A

The above link will be updated soon so stay tuned and till then try the OTA or Kies method.

That’s it! If you have successfully updated your AT&T S5 G900A on G900AUCS4DQC1 firmware, give us your feedback.

We will be happy to hear your thoughts

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