A166U1UES9DZH1 – Galaxy A16 5G firmware

Build A166U1UES9DZH1 is a security update for the Galaxy A16 5G (SM-A166U1) on Android 16 (One UI 8). It first appeared on Samsung's servers on Sep 14, 2026 (method) and has reached 13 regions so far. It raises the bootloader bit from 8 to 9: once installed, the device no longer accepts firmware with bit 8 or lower, so a downgrade to A166U1UES8DZG1 is blocked. Samsung still serves this file.

Model
SM-A166U1
Android
Android 16
Type
Security
Bootloader bit
9
First released
Sep 14, 2026
Regions
13

Rollout timeline by region

The date each region code (CSC) first received A166U1UES9DZH1, counted from the first release.

CSCRegionReleasedRolloutVersion (PDA/CSC/MODEM)
ACGUSA (C Spire)Sep 14, 2026day 0A166U1UES9DZH1/A166U1OYM9DZH1/A166U1UES9DZH1
AIOUSA (Cricket)Sep 14, 2026day 0A166U1UES9DZH1/A166U1OYM9DZH1/A166U1UES9DZH1
ATTUSA (AT&T)Sep 14, 2026day 0A166U1UES9DZH1/A166U1OYM9DZH1/A166U1UES9DZH1
CCTUSA (Comcast)Sep 14, 2026day 0A166U1UES9DZH1/A166U1OYM9DZH1/A166U1UES9DZH1
DSAUSASep 14, 2026day 0A166U1UES9DZH1/A166U1OYM9DZH1/A166U1UES9DZH1
DSHUSASep 14, 2026day 0A166U1UES9DZH1/A166U1OYM9DZH1/A166U1UES9DZH1
LRAUSA (Bluegrass)Sep 14, 2026day 0A166U1UES9DZH1/A166U1OYM9DZH1/A166U1UES9DZH1
TMBUSA (T-Mobile)Sep 14, 2026day 0A166U1UES9DZH1/A166U1OYM9DZH1/A166U1UES9DZH1
TMKUSA (MetroPCS)Sep 14, 2026day 0A166U1UES9DZH1/A166U1OYM9DZH1/A166U1UES9DZH1
USCUSA (US Cellular)Sep 14, 2026day 0A166U1UES9DZH1/A166U1OYM9DZH1/A166U1UES9DZH1
VZWUSA (Verizon)Sep 14, 2026day 0A166U1UES9DZH1/A166U1OYM9DZH1/A166U1UES9DZH1
XAAUSA (unlocked)Sep 14, 2026day 0A166U1UES9DZH1/A166U1OYM9DZH1/A166U1UES9DZH1
XARUSA (Cellular South)Sep 14, 2026day 0A166U1UES9DZH1/A166U1OYM9DZH1/A166U1UES9DZH1

Download and release notes

samloader download -m SM-A166U1 -r XAA -v A166U1UES9DZH1/A166U1OYM9DZH1/A166U1UES9DZH1

Samsung's release notes and security patch level for this update: SM-A166U1 / XAA on doc.samsungmobile.com. What each part of the build number means: decode A166U1UES9DZH1.