A366U1UESACZH1 – Galaxy A36 5G firmware

Build A366U1UESACZH1 is a security update for the Galaxy A36 5G (SM-A366U1) 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 A366U1UES9CZG2 is blocked. Samsung still serves this file.

Model
SM-A366U1
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 A366U1UESACZH1, counted from the first release.

CSCRegionReleasedRolloutVersion (PDA/CSC/MODEM)
ACGUSA (C Spire)Sep 10, 2026day 0A366U1UESACZH1/A366U1OYMACZH1/A366U1UESACZH1
AIOUSA (Cricket)Sep 10, 2026day 0A366U1UESACZH1/A366U1OYMACZH1/A366U1UESACZH1
ATTUSA (AT&T)Sep 10, 2026day 0A366U1UESACZH1/A366U1OYMACZH1/A366U1UESACZH1
CCTUSA (Comcast)Sep 10, 2026day 0A366U1UESACZH1/A366U1OYMACZH1/A366U1UESACZH1
DSAUSASep 10, 2026day 0A366U1UESACZH1/A366U1OYMACZH1/A366U1UESACZH1
DSHUSASep 10, 2026day 0A366U1UESACZH1/A366U1OYMACZH1/A366U1UESACZH1
LRAUSA (Bluegrass)Sep 10, 2026day 0A366U1UESACZH1/A366U1OYMACZH1/A366U1UESACZH1
TMBUSA (T-Mobile)Sep 10, 2026day 0A366U1UESACZH1/A366U1OYMACZH1/A366U1UESACZH1
TMKUSA (MetroPCS)Sep 10, 2026day 0A366U1UESACZH1/A366U1OYMACZH1/A366U1UESACZH1
USCUSA (US Cellular)Sep 10, 2026day 0A366U1UESACZH1/A366U1OYMACZH1/A366U1UESACZH1
VZWUSA (Verizon)Sep 10, 2026day 0A366U1UESACZH1/A366U1OYMACZH1/A366U1UESACZH1
XAAUSA (unlocked)Sep 10, 2026day 0A366U1UESACZH1/A366U1OYMACZH1/A366U1UESACZH1
XARUSA (Cellular South)Sep 10, 2026day 0A366U1UESACZH1/A366U1OYMACZH1/A366U1UESACZH1

Download and release notes

samloader download -m SM-A366U1 -r XAA -v A366U1UESACZH1/A366U1OYMACZH1/A366U1UESACZH1

Samsung's release notes and security patch level for this update: SM-A366U1 / XAA on doc.samsungmobile.com. What each part of the build number means: decode A366U1UESACZH1.