M556BXXS4CYL1 – Galaxy M55 5G firmware

Build M556BXXS4CYL1 is a security update for the Galaxy M55 5G (SM-M556B) on Android 16 (One UI 8). It first appeared on Samsung's servers on Dec 22, 2025 (method) and has reached 13 regions so far. It keeps bootloader bit 4, so downgrading to the previous build M556BXXU4CYJ4 is still possible. Samsung still serves this file.

Model
SM-M556B
Android
Android 16
Type
Security
Bootloader bit
4
First released
Dec 22, 2025
Regions
13

Rollout timeline by region

The date each region code (CSC) first received M556BXXS4CYL1, counted from the first release.

CSCRegionReleasedRolloutVersion (PDA/CSC/MODEM)
BNGBelgiumDec 22, 2025day 0M556BXXS4CYL1/M556BODM4CYL1/M556BXXS4CYL1
INSIndiaDec 22, 2025day 0M556BXXS4CYL1/M556BODM4CYL1/M556BXXS4CYL1
NPBNepalDec 22, 2025day 0M556BXXS4CYL1/M556BODM4CYL1/M556BXXS4CYL1
SLKSri LankaDec 22, 2025day 0M556BXXS4CYL1/M556BODM4CYL1/M556BXXS4CYL1
EGYEgyptDec 28, 2025+6 daysM556BXXS4CYL1/M556BOJM4CYL1/M556BXXS4CYL1
ILOIsraelDec 28, 2025+6 daysM556BXXS4CYL1/M556BOJM4CYL1/M556BXXS4CYL1
MIDMiddle EastDec 28, 2025+6 daysM556BXXS4CYL1/M556BOJM4CYL1/M556BXXS4CYL1
XXVVietnamDec 28, 2025+6 daysM556BXXS4CYL1/M556BOLM4CYL1/M556BXXS4CYL1
CHOChileJan 7, 2026+16 daysM556BXXS4CYL1/M556BOWO4CYL1/M556BXXS4CYL1
COOColombiaJan 7, 2026+16 daysM556BXXS4CYL1/M556BOWO4CYL1/M556BXXS4CYL1
PEOPeruJan 7, 2026+16 daysM556BXXS4CYL1/M556BOWO4CYL1/M556BXXS4CYL1
TPAPanamaJan 7, 2026+16 daysM556BXXS4CYL1/M556BOWO4CYL1/M556BXXS4CYL1
ZTOBrazilJan 7, 2026+16 daysM556BXXS4CYL1/M556BOWO4CYL1/M556BXXS4CYL1

Download and release notes

samloader download -m SM-M556B -r INS -v M556BXXS4CYL1/M556BODM4CYL1/M556BXXS4CYL1

Samsung's release notes and security patch level for this update: SM-M556B / INS on doc.samsungmobile.com. What each part of the build number means: decode M556BXXS4CYL1.