Samsung Galaxy S21 Ultra 5G G998NKSS8GYC1
SM-G998N 1 country Android 14

Samsung Galaxy S21 Ultra 5G G998NKSS8GYC1 Firmware

Samsung Galaxy S21 Ultra 5G G998NKSS8GYC1 is an Android 14 firmware for South Korea (KOO, KTC, LUC, SKC). It is the same firmware configured per region and carrier (CSC). Find your country below, verify the file and download for free. Compared with the previous build G998NKSS8GYA1: security patch 2025-03-01 instead of 2025-01-01. A newer build for SM-G998N is available: G998NKSSCHZA9.

OS updates guaranteed until: Android 15Security updates until: Jan 29, 2026
Download firmware
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Android 14
OS Version
2025-03-20
Build Date
2025-03-01
Security patch
1
Countries
4
CSC codes
8
Bootloader binary

Bootloader binary 8. Flashing firmware with a lower binary is usually blocked by Samsung anti-rollback.

Newer builds of Samsung Galaxy S21 Ultra 5G use bootloader binary C (12) (latest: G998NKSSCHZA9). If your device already runs binary C (12), this build cannot be flashed.

All regional downloads

Pick your region (CSC) to download the matching firmware package.

Paste your current build number from Settings > About phone (About tablet) > Software information, or the output of *#1234#.
    MODEM/CP Version: G998NKOS8GYC1
    ModelRegionCSC VersionRelease dateSizeFile nameDownload
    SM-G998N
    KOO, KTC, LUC, SKC South Korea
    		G998NOKR8GYC1 2025-03-20 7.609 GiB
    SM-G998N_4_20250307092440_h6esfym3jx_fac.zip
    		Download

    No matching downloads

    How to flash G998NKSS8GYC1

    • G998NKSS8GYC1 has bootloader binary 8. Your device must run binary 8 or lower: it is the 5th character from the end of your current build number.
    • CSC: Use CSC for a clean install, to change the region (CSC code), to downgrade or to repair a device that does not boot.
    • HOME_CSC: Use HOME_CSC to update the same model and region while keeping your data. Back up anyway: a failed update can still require a reset.
    • The Download Mode key combo depends on the model: see all combos.
    Full flashing guide
    Beware: Manually flashing firmwares may brick your device. Use it at your own risk and follow our tutorial steps.

    Security patch: March 2025

    SMR Mar-2025 fixes 55 vulnerabilities, 11 of them critical. Android Security Bulletin: 49, Samsung-specific issues (SVE): 6.

    Most severe Samsung fixes:

    • high Improper access control in SecSettingsIntelligence (CVE-2025-20903)

    All fixes and Galaxy models with this patch

    Rollout of G998NKSS8GYC1 by region

    Samsung released this build in all regions (4) on the same day, March 20, 2025.

    Device specifications

    • Launched withAndroid 11
    • Display diagonal17.3 cm (6.8")
    • Display resolution3200 x 1440 pixels
    • Display typeDynamic AMOLED 2X
    • RAM12 GB
    • Rear camera resolution108 MP
    • Rear camera typeQuad camera
    • Battery capacity5000 mAh
    • Weight228 g

    Specifications of SM-G998, a regional variant of the same device. Chipset and SIM lines are left out: they can differ by region.

    Frequently Asked Questions

    G998NKSS8GYC1 is Android 14 firmware for Samsung Galaxy S21 Ultra 5G, released for South Korea (KOO, KTC, LUC, SKC). It includes the 2025-03-01 security patch. Samsung built it on 2025-03-20.

    SMR Mar-2025 fixes 55 vulnerabilities, 11 of them critical. Android Security Bulletin: 49, Samsung-specific issues (SVE): 6.

    No. A newer build for SM-G998N is available: G998NKSSCHZA9. Install it instead of G998NKSS8GYC1 unless you need this exact version. The previous build was G998NKSS8GYA1.

    Download the package for your region (CSC) and unzip it. In Odin, load each file into the slot with the same name: BL, AP, CP (if the package has one) and CSC, or HOME_CSC to keep your data. Odin checks the built-in checksum of every .tar.md5 file before flashing. The download is 7.609 GiB; keep about twice that free on the computer to unzip it. The Samsung Galaxy S21 Ultra 5G must be on bootloader binary 8 or lower.

    This build uses bootloader binary 8. It can be flashed on a Samsung Galaxy S21 Ultra 5G running binary 8 or lower; if the device already has a higher binary, Odin stops with "SW REV CHECK FAIL". 4 other builds of this model use the same binary, so you can switch between them in both directions.

    Other builds and changelog for Samsung Galaxy S21 Ultra 5G

    No changelog details available.
    Model firmware by region