Samsung Galaxy S21 5G (SM-G991U) Firmware Overview
What is the latest SM-G991U firmware?
G991USQSJHZB1, released March 23, 2026 with Android 15. It is a security update on bootloader binary 19. The archive holds 29 official builds across 9 regions (CSC).
Is the Samsung Galaxy S21 5G 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-G991U firmware?
Only to builds with the same bootloader binary (the Bit column) or higher. In the archive the binary of this model rose from 17 to 19:
- Binary 19 — since Jan 2026
- Binary 18 — since Dec 2025
- Binary 17 — since Sep 2025
A phone already on binary 19 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 19 build. How to read a build number.
All SM-G991U firmware builds
| Build / PDA | Bit | Region (CSC) | Android | Date | Download Link |
|---|---|---|---|---|---|
|
G991USQSJHZB1
Security update
|
19 | VZW | 15 |
2026-03-23 | Download |
|
G991USQSJHZB1
Security update
|
19 | DSA | 15 |
2026-03-19 | Download |
|
G991USQSJHZB1
Security update
|
19 | SPR | 15 |
2026-03-19 | Download |
|
G991USQSJHZB1
Security update
|
19 | TMB | 15 |
2026-03-19 | Download |
|
G991USQSJHZB1
Security update
|
19 | CHA | 15 |
2026-03-19 | Download |
|
G991USQSJHZB1
Security update
|
19 | CCT | 15 |
2026-03-19 | Download |
|
G991USQSJHZB1
Security update
|
19 | DSH | 15 |
2026-03-19 | Download |
|
G991USQSJHZB1
Security update
|
19 | ATT | 15 |
2026-03-18 | Download |
|
G991USQSJHZB1
Security update
|
19 | USC | 15 |
2026-03-18 | Download |
|
G991USQSJHZAA
Security update
|
19 | VZW | 15 |
2026-02-02 | Download |
|
G991USQSJHZAA
Security update
|
19 | ATT | 15 |
2026-02-02 | Download |
|
G991USQSJHZAA
Security update
|
19 | CHA | 15 |
2026-01-29 | Download |
|
G991USQSJHZAA
Security update
|
19 | CCT | 15 |
2026-01-29 | Download |
|
G991USQSJHZAA
Security update
|
19 | USC | 15 |
2026-01-28 | Download |
|
G991USQSJHZAA
Security update
|
19 | DSH | 15 |
2026-01-28 | Download |
|
G991USQSJHZAA
Security update
|
19 | DSA | 15 |
2026-01-28 | Download |
|
G991USQSJHZAA
Security update
|
19 | TMB | 15 |
2026-01-28 | Download |
|
G991USQSJHZAA
Security update
|
19 | SPR | 15 |
2026-01-28 | Download |
|
G991USQSIHYL1
Security update
|
18 | VZW | 15 |
2025-12-22 | Download |
|
G991USQSIHYL1
Security update
|
18 | CHA | 15 |
2025-12-19 | Download |
|
G991USQSIHYL1
Security update
|
18 | CCT | 15 |
2025-12-19 | Download |
|
G991USQSIHYL1
Security update
|
18 | ATT | 15 |
2025-12-18 | Download |
|
G991USQSIHYL1
Security update
|
18 | USC | 15 |
2025-12-17 | Download |
|
G991USQSIHYL1
Security update
|
18 | SPR | 15 |
2025-12-17 | Download |
|
G991USQSIHYL1
Security update
|
18 | TMB | 15 |
2025-12-17 | Download |
|
G991USQSIHYL1
Security update
|
18 | DSH | 15 |
2025-12-17 | Download |
|
G991USQSIHYL1
Security update
|
18 | DSA | 15 |
2025-12-17 | Download |
|
G991USQSHHYI1
Security update
|
17 | VZW | 15 |
2025-09-30 | Download |
|
G991USQSHHYI1
Security update
|
17 | CHA | 15 |
2025-09-26 | Download |
Latest SM-G991U 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 |
|---|---|---|---|---|
| ATT | G991USQSJHZB1 | 19 | 15 | 2026-03-18 |
| CCT | G991USQSJHZB1 | 19 | 15 | 2026-03-19 |
| CHA | G991USQSJHZB1 | 19 | 15 | 2026-03-19 |
| DSA | G991USQSJHZB1 | 19 | 15 | 2026-03-19 |
| DSH | G991USQSJHZB1 | 19 | 15 | 2026-03-19 |
| SPR | G991USQSJHZB1 | 19 | 15 | 2026-03-19 |
| TMB | G991USQSJHZB1 | 19 | 15 | 2026-03-19 |
| USC | G991USQSJHZB1 | 19 | 15 | 2026-03-18 |
| VZW | G991USQSJHZB1 | 19 | 15 | 2026-03-23 |
How to Flash SM-G991U Firmware
Put the Samsung Galaxy S21 5G 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 19 or higher if your phone is already on the latest firmware. Use HOME_CSC to keep your data, CSC for a full wipe.