A266U1UESACZH3 – Galaxy A26 5G firmware

Build A266U1UESACZH3 is a security update for the Galaxy A26 5G (SM-A266U1) on Android 16 (One UI 8). It first appeared on Samsung's servers on Sep 10, 2026 (method) and has reached 13 regions so far. It raises the bootloader bit from 9 to 10: once installed, the device no longer accepts firmware with bit 9 or lower, so a downgrade to A266U1UES9CZG2 is blocked. Samsung still serves this file.

Model
SM-A266U1
Android
Android 16
Type
Security
Bootloader bit
10
First released
Sep 10, 2026
Regions
13

Rollout timeline by region

The date each region code (CSC) first received A266U1UESACZH3, counted from the first release.

CSCRegionReleasedRolloutVersion (PDA/CSC/MODEM)
ACGUSA (C Spire)Sep 10, 2026day 0A266U1UESACZH3/A266U1OYMACZH3/A266U1UESACZH3
AIOUSA (Cricket)Sep 10, 2026day 0A266U1UESACZH3/A266U1OYMACZH3/A266U1UESACZH3
ATTUSA (AT&T)Sep 10, 2026day 0A266U1UESACZH3/A266U1OYMACZH3/A266U1UESACZH3
CCTUSA (Comcast)Sep 10, 2026day 0A266U1UESACZH3/A266U1OYMACZH3/A266U1UESACZH3
DSAUSASep 10, 2026day 0A266U1UESACZH3/A266U1OYMACZH3/A266U1UESACZH3
DSHUSASep 10, 2026day 0A266U1UESACZH3/A266U1OYMACZH3/A266U1UESACZH3
LRAUSA (Bluegrass)Sep 10, 2026day 0A266U1UESACZH3/A266U1OYMACZH3/A266U1UESACZH3
TMBUSA (T-Mobile)Sep 10, 2026day 0A266U1UESACZH3/A266U1OYMACZH3/A266U1UESACZH3
TMKUSA (MetroPCS)Sep 10, 2026day 0A266U1UESACZH3/A266U1OYMACZH3/A266U1UESACZH3
USCUSA (US Cellular)Sep 10, 2026day 0A266U1UESACZH3/A266U1OYMACZH3/A266U1UESACZH3
VZWUSA (Verizon)Sep 10, 2026day 0A266U1UESACZH3/A266U1OYMACZH3/A266U1UESACZH3
XAAUSA (unlocked)Sep 10, 2026day 0A266U1UESACZH3/A266U1OYMACZH3/A266U1UESACZH3
XARUSA (Cellular South)Sep 10, 2026day 0A266U1UESACZH3/A266U1OYMACZH3/A266U1UESACZH3

Download and release notes

samloader download -m SM-A266U1 -r XAA -v A266U1UESACZH3/A266U1OYMACZH3/A266U1UESACZH3

Samsung's release notes and security patch level for this update: SM-A266U1 / XAA on doc.samsungmobile.com. What each part of the build number means: decode A266U1UESACZH3.