SM-G998N 1 country Android 11

Samsung Galaxy S21 Ultra 5G G998NKSS3AUIN Firmware

Name: Samsung Galaxy S21 Ultra 5G (SM-G998N)
Brand: Samsung
Availability: InStock

Samsung Galaxy S21 Ultra 5G G998NKSS3AUIN is an Android 11 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 G998NKSU3AUIG, Android and the bootloader binary are unchanged, so you can switch between the two in both directions. A newer build for SM-G998N is available: G998NKSSCHZA9.

OS updates guaranteed until: Android 15Security updates until: Jan 23, 2026

9.4/10 (485)17,248 times

Android 11

OS Version

2021-10-14

Build Date

2021-10-01

Security patch

Countries

CSC codes

Bootloader binary

Bootloader binary 3. 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.

Will it work on my device?

Paste your current build number from Settings > About phone (About tablet) > Software information, or the output of *#1234#.

MODEM/CP Version: G998NKOU3AUIG

Model	Region	CSC Version	Release date	Size	File name	Download
SM-G998N	KOO, KTC, LUC, SKC South Korea	G998NOKR3AUIN	2021-10-14	6.102 GiB	SM-G998N_1_20211001060035_5tuw7fgeqk_fac.zip

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.

How to flash G998NKSS3AUIN

Install Samsung USB Drivers:Download Official Drivers
Download Odin Flash Tool:

G998NKSS3AUIN has bootloader binary 3. Your device must run binary 3 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.

Frequently Asked Questions

G998NKSS3AUIN is Android 11 firmware for Samsung Galaxy S21 Ultra 5G, released for South Korea (KOO, KTC, LUC, SKC). It includes the 2021-10-01 security patch. Samsung built it on 2021-10-14.

No. A newer build for SM-G998N is available: G998NKSSCHZA9. Install it instead of G998NKSS3AUIN unless you need this exact version. The previous build was G998NKSU3AUIG.

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 6.102 GiB; keep about twice that free on the computer to unzip it. The Samsung Galaxy S21 Ultra 5G must be on bootloader binary 3 or lower.

This build uses bootloader binary 3. It can be flashed on a Samsung Galaxy S21 Ultra 5G running binary 3 or lower; if the device already has a higher binary, Odin stops with "SW REV CHECK FAIL". 23 other builds of this model use the same binary, so you can switch between them in both directions.