Samsung SM-G991N Firmware Overview
What is the latest SM-G991N firmware?
G991NKSSCHZA9, released March 12, 2026 with Android 15. It is a security update on bootloader binary 12. The archive holds 20 official builds across 4 regions (CSC). Each one is the full stock ROM (flash file) for Odin, not an OTA patch.
Is the Samsung SM-G991N still getting updates?
The last build arrived in March 2026. Updates have slowed down — models late in their support period move to quarterly or half-yearly security patches before they stop.
Can I downgrade the SM-G991N firmware?
Only to builds with the same bootloader binary (the Bit column) or higher. In the archive the binary of this model rose from 9 to 12:
- Binary 12 — since Jan 2026
- Binary 11 — since Nov 2025
- Binary 10 — since Aug 2025
- Binary 9 — since May 2025
A phone already on binary 12 rejects builds with a lower binary in Odin ("SW REV CHECK FAIL"), so it can go back to an earlier Android version only if that version has a binary 12 build. How to read a build number.
All SM-G991N firmware builds
| Build / PDA | Bit | Region (CSC) | Android | Date | Download Link |
|---|---|---|---|---|---|
|
G991NKSSCHZA9
Security update
|
12 | SKC | 15 |
2026-03-12 | Download |
|
G991NKSSCHZA9
Security update
|
12 | KOO | 15 |
2026-03-12 | Download |
|
G991NKSSCHZA9
Security update
|
12 | LUC | 15 |
2026-03-12 | Download |
|
G991NKSSCHZA9
Security update
|
12 | KTC | 15 |
2026-03-12 | Download |
|
G991NKSSCHZA5
Security update
|
12 | SKC | 15 |
2026-01-22 | Download |
|
G991NKSSCHZA5
Security update
|
12 | KTC | 15 |
2026-01-22 | Download |
|
G991NKSSCHZA5
Security update
|
12 | KOO | 15 |
2026-01-22 | Download |
|
G991NKSSCHZA5
Security update
|
12 | LUC | 15 |
2026-01-22 | Download |
|
G991NKSSBHYK5
Security update
|
11 | SKC | 15 |
2025-11-27 | Download |
|
G991NKSSBHYK5
Security update
|
11 | KTC | 15 |
2025-11-27 | Download |
|
G991NKSSBHYK5
Security update
|
11 | LUC | 15 |
2025-11-27 | Download |
|
G991NKSSBHYK5
Security update
|
11 | KOO | 15 |
2025-11-27 | Download |
|
G991NKSSAHYH5
Security update
|
10 | SKC | 15 |
2025-08-25 | Download |
|
G991NKSSAHYH5
Security update
|
10 | LUC | 15 |
2025-08-25 | Download |
|
G991NKSSAHYH5
Security update
|
10 | KTC | 15 |
2025-08-25 | Download |
|
G991NKSSAHYH5
Security update
|
10 | KOO | 15 |
2025-08-25 | Download |
|
G991NKSS9HYE5
Security update
|
9 | KOO | 15 |
2025-06-09 | Download |
|
G991NKSS9HYE5
Security update
|
9 | SKC | 15 |
2025-06-09 | Download |
|
G991NKSS9HYE5
Security update
|
9 | KTC | 15 |
2025-06-09 | Download |
|
G991NKSS9HYE5
Security update
|
9 | LUC | 15 |
2025-06-09 | Download |
Latest SM-G991N Firmware by Region
The newest build for each region (CSC) code. Not sure which region your phone uses? See the CSC code guide.
| Region | Latest build | Bit | Android | Date |
|---|---|---|---|---|
| KOO | G991NKSSCHZA9 | 12 | 15 | 2026-03-12 |
| KTC | G991NKSSCHZA9 | 12 | 15 | 2026-03-12 |
| LUC | G991NKSSCHZA9 | 12 | 15 | 2026-03-12 |
| SKC | G991NKSSCHZA9 | 12 | 15 | 2026-03-12 |
How to Flash SM-G991N Firmware
Put the Samsung SM-G991N into Download Mode, load the BL, AP, CP and CSC files into Odin on a Windows PC and press Start. Pick a build with Bit 12 or higher if your phone is already on the latest firmware. Use HOME_CSC to keep your data, CSC for a full wipe.