Extreme Android User
Aug 17, 2010
Cotswolds, England
N.B. Not to be confused with the second August update and Security patch... AUHB

This latest release is the 17th for the Global, Exynos, S21 series and is currently being rolled out by Samsung only 11 days after the second August update, AUHB which is still, currently, being rolled out.

This update is for device security.

Initially, as always, this is a staged roll out to the non-carrier branded, stock Samsung CSC codes first.

The Galaxy S21 Global, Exynos, devices that will receive this update are...
  • S21 5G model SM-G991B
  • S21+ 5G model SM-G996B
  • S21 Ultra 5G model SM-G998B
This latest release replaces the previous G99*BXXU3AUHB build.

It is a FOTA, (Firmware Over The Air), update and you can check... Settings > Software update... to see if it is available for you. Alternatively, you can connect to the Samsung PC suite, Smart Switch and check via that.

  • Device security

The update = G99*BXXS3AUHD

Download = 203.68MB

Build date = 19 August 2021

Release date = 04 September 2021

Camera version = (No change)

One UI version = 3.1

Android Security patch = 01 September 2021

This is the 17th stable update in 223 days. Average = 1 update every 13 days.

(N.B. This post will be updated as more information becomes available)

AUHD System information

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As far as I can tell and from the, "S", in the Build number, this is just for the September Android Security patch on the previous, AUHB, update. Both CSC and Baseband are unchanged from AUHB.
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Samsung update AUHD


As suspected, this update is merely the September Android Security patch.

This quick release, so soon after the previous AUHB, may indicate a readiness for the Android 12 Beta One UI 4.0 test firmware to be rolled out imminently to qualifying countries and devices.