S921NKSSGDZG1 – Galaxy S24 firmware

Build S921NKSSGDZG1 is a security update for the Galaxy S24 (SM-S921N) on Android 16 (One UI 8). It first appeared on Samsung's servers on Jul 14, 2026 (method) and has reached 4 regions so far. It raises the bootloader bit from 15 to 16: once installed, the device no longer accepts firmware with bit 15 or lower, so a downgrade to S921NKSSFDZF3 is blocked. Samsung still serves this file.

Model
SM-S921N
Android
Android 16
Type
Security
Bootloader bit
16
First released
Jul 14, 2026
Regions
4

Rollout timeline by region

The date each region code (CSC) first received S921NKSSGDZG1, counted from the first release.

CSCRegionReleasedRolloutVersion (PDA/CSC/MODEM)
KOOSouth KoreaJul 14, 2026day 0S921NKSSGDZG1/S921NOKRGDZG1/S921NKSSGDZG1
KTCSouth Korea (KT)Jul 14, 2026day 0S921NKSSGDZG1/S921NOKRGDZG1/S921NKSSGDZG1
LUCSouth Korea (LG U+)Jul 14, 2026day 0S921NKSSGDZG1/S921NOKRGDZG1/S921NKSSGDZG1
SKCSouth Korea (SKT)Jul 14, 2026day 0S921NKSSGDZG1/S921NOKRGDZG1/S921NKSSGDZG1

Download and release notes

samloader download -m SM-S921N -r KOO -v S921NKSSGDZG1/S921NOKRGDZG1/S921NKSSGDZG1

Samsung's release notes and security patch level for this update: SM-S921N / KOO on doc.samsungmobile.com. What each part of the build number means: decode S921NKSSGDZG1.