A166U1UES7CZDG – Galaxy A16 5G firmware

Build A166U1UES7CZDG 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 May 13, 2026 (method) and has reached 13 regions so far. It raises the bootloader bit from 6 to 7: once installed, the device no longer accepts firmware with bit 6 or lower, so a downgrade to A166U1UES6CZB6 is blocked. Samsung still serves this file.

Model
SM-A166U1
Android
Android 16
Type
Security
Bootloader bit
7
First released
May 13, 2026
Regions
13

Rollout timeline by region

The date each region code (CSC) first received A166U1UES7CZDG, counted from the first release.

CSCRegionReleasedRolloutVersion (PDA/CSC/MODEM)
ACGUSA (C Spire)May 13, 2026day 0A166U1UES7CZDG/A166U1OYM7CZDG/A166U1UES7CZDG
AIOUSA (Cricket)May 13, 2026day 0A166U1UES7CZDG/A166U1OYM7CZDG/A166U1UES7CZDG
ATTUSA (AT&T)May 13, 2026day 0A166U1UES7CZDG/A166U1OYM7CZDG/A166U1UES7CZDG
CCTUSA (Comcast)May 13, 2026day 0A166U1UES7CZDG/A166U1OYM7CZDG/A166U1UES7CZDG
DSAUSAMay 13, 2026day 0A166U1UES7CZDG/A166U1OYM7CZDG/A166U1UES7CZDG
DSHUSAMay 13, 2026day 0A166U1UES7CZDG/A166U1OYM7CZDG/A166U1UES7CZDG
LRAUSA (Bluegrass)May 13, 2026day 0A166U1UES7CZDG/A166U1OYM7CZDG/A166U1UES7CZDG
TMBUSA (T-Mobile)May 13, 2026day 0A166U1UES7CZDG/A166U1OYM7CZDG/A166U1UES7CZDG
TMKUSA (MetroPCS)May 13, 2026day 0A166U1UES7CZDG/A166U1OYM7CZDG/A166U1UES7CZDG
USCUSA (US Cellular)May 13, 2026day 0A166U1UES7CZDG/A166U1OYM7CZDG/A166U1UES7CZDG
VZWUSA (Verizon)May 13, 2026day 0A166U1UES7CZDG/A166U1OYM7CZDG/A166U1UES7CZDG
XAAUSA (unlocked)May 13, 2026day 0A166U1UES7CZDG/A166U1OYM7CZDG/A166U1UES7CZDG
XARUSA (Cellular South)May 13, 2026day 0A166U1UES7CZDG/A166U1OYM7CZDG/A166U1UES7CZDG

Download and release notes

samloader download -m SM-A166U1 -r XAA -v A166U1UES7CZDG/A166U1OYM7CZDG/A166U1UES7CZDG

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 A166U1UES7CZDG.