S921BXXSIEZJ1 – Galaxy S24 firmware

Build S921BXXSIEZJ1 is a security update for the Galaxy S24 (SM-S921B) on Android 17 (One UI 9). It first appeared on Samsung's servers on Oct 25, 2026 (method) and has reached 67 regions so far. It raises the bootloader bit from 17 to 18: once installed, the device no longer accepts firmware with bit 17 or lower, so a downgrade to S921BXXUHEZIF is blocked. Samsung still serves this file.

Model
SM-S921B
Android
Android 17
Type
Security
Bootloader bit
18
First released
Oct 25, 2026
Regions
67

Rollout timeline by region

The date each region code (CSC) first received S921BXXSIEZJ1, counted from the first release.

CSCRegionReleasedRolloutVersion (PDA/CSC/MODEM)
EUYEurope (Multi-CSC)Oct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
BOGFrance (Bouygues)Oct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
CAUCaucasusOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
EUXEurope (Multi-CSC)Oct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
EVRUnited Kingdom (EE)Oct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
MEOPortugal (MEO)Oct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
MOBAustria (A1)Oct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
MOTSlovenia (Telekom)Oct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
MSRSerbiaOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
O2CCzech Republic (O2)Oct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
PLSPoland (Plus)Oct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
PRTPoland (Play)Oct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
SERRussiaOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
SFRFrance (SFR)Oct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
SIMSlovenia (A1)Oct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
SKZKazakhstanOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
SWCSwitzerlandOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
TOPSerbia/MontenegroOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
VIPCroatia (A1)Oct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
ACRGhanaOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
AFGAfghanistanOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
AFRAfricaOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
DKRSenegalOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
ECTNigeriaOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
EGYEgyptOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
GLBPhilippines (Globe)Oct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
ILOIsraelOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
KSASaudi ArabiaOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
LYSLibyaOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
MIDMiddle EastOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
MM1Singapore (M1)Oct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
MWDMoroccoOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
OPSAustralia (Optus)Oct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
PAKPakistanOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
PKDPakistanOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
SINSingapore (Singtel)Oct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
STHSingapore (StarHub)Oct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
TELAustralia (Telstra)Oct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
THLThailandOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
TUNTunisiaOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
TURTurkeyOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
VAUAustralia (Vodafone)Oct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
XFASouth AfricaOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
XFESouth AfricaOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
XFVSouth Africa (Vodacom)Oct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
XIDIndonesiaOct 25, 2026day 0S921BXXSIEZJ1/S921BOLEIEZJ1/S921BXXSIEZJ1
XMEMalaysiaOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
XNZNew ZealandOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
XSAAustraliaOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
XSGUnited Arab EmiratesOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
XSPSingaporeOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
XTCPhilippinesOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
XXVVietnamOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
INSIndiaOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
NPBNepalOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
SLKSri LankaOct 25, 2026day 0S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1
BVOBoliviaOct 28, 2026+3 daysS921BXXSIEZJ1/S921BOWOIEZJ1/S921BXXSIEZJ1
GTOGuatemalaOct 28, 2026+3 daysS921BXXSIEZJ1/S921BOWOIEZJ1/S921BXXSIEZJ1
TPAPanamaOct 28, 2026+3 daysS921BXXSIEZJ1/S921BOWOIEZJ1/S921BXXSIEZJ1
IUSMexico (AT&T)Nov 5, 2026+11 daysS921BXXSIEZJ1/S921BOWOIEZJ1/S921BXXSIEZJ1
MXOMexicoNov 5, 2026+11 daysS921BXXSIEZJ1/S921BOWOIEZJ1/S921BXXSIEZJ1
TCEMexico (Telcel)Nov 5, 2026+11 daysS921BXXSIEZJ1/S921BOWOIEZJ1/S921BXXSIEZJ1
TMMMyanmarNov 5, 2026+11 daysS921BXXSIEZJ1/S921BOWOIEZJ1/S921BXXSIEZJ1
ZTABrazil (Claro)Nov 5, 2026+11 daysS921BXXSIEZJ1/S921BOWOIEZJ1/S921BXXSIEZJ1
ZTMBrazil (TIM)Nov 5, 2026+11 daysS921BXXSIEZJ1/S921BOWOIEZJ1/S921BXXSIEZJ1
ZTOBrazilNov 5, 2026+11 daysS921BXXSIEZJ1/S921BOWOIEZJ1/S921BXXSIEZJ1
ZVVBrazil (Vivo)Nov 5, 2026+11 daysS921BXXSIEZJ1/S921BOWOIEZJ1/S921BXXSIEZJ1

Download and release notes

samloader download -m SM-S921B -r EUX -v S921BXXSIEZJ1/S921BOXMIEZJ1/S921BXXSIEZJ1

Samsung's release notes and security patch level for this update: SM-S921B / EUX on doc.samsungmobile.com. What each part of the build number means: decode S921BXXSIEZJ1.