G991USQSGHYF2 – Galaxy S21 5G firmware

Build G991USQSGHYF2 is a security update for the Galaxy S21 5G (SM-G991U) on Android 15 (One UI 7). It first appeared on Samsung's servers on Jun 25, 2025 (method) and has reached 8 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 G991USQSFHYE2 is blocked. Samsung still serves this file.

Model
SM-G991U
Android
Android 15
Type
Security
Bootloader bit
16
First released
Jun 25, 2025
Regions
8

Rollout timeline by region

The date each region code (CSC) first received G991USQSGHYF2, counted from the first release.

CSCRegionReleasedRolloutVersion (PDA/CSC/MODEM)
SPRUSA (Sprint)Jun 25, 2025day 0G991USQSGHYF2/G991UOYNGHYF2/G991USQSGHYF2
TMBUSA (T-Mobile)Jun 25, 2025day 0G991USQSGHYF2/G991UOYNGHYF2/G991USQSGHYF2
ATTUSA (AT&T)Jun 25, 2025day 0G991USQSGHYF2/G991UOYNGHYF2/G991USQSGHYF2
CCTUSA (Comcast)Jun 25, 2025day 0G991USQSGHYF2/G991UOYNGHYF2/G991USQSGHYF2
VZWUSA (Verizon)Jun 25, 2025day 0G991USQSGHYF2/G991UOYNGHYF2/G991USQSGHYF2
DSAUSAJun 26, 2025+1 dayG991USQSGHYF2/G991UOYNGHYF2/G991USQSGHYF2
DSHUSAJun 26, 2025+1 dayG991USQSGHYF2/G991UOYNGHYF2/G991USQSGHYF2
USCUSA (US Cellular)Jun 30, 2025+5 daysG991USQSGHYF2/G991UOYNGHYF2/G991USQSGHYF2

Download and release notes

samloader download -m SM-G991U -r SPR -v G991USQSGHYF2/G991UOYNGHYF2/G991USQSGHYF2

Samsung's release notes and security patch level for this update: SM-G991U / SPR on doc.samsungmobile.com. What each part of the build number means: decode G991USQSGHYF2.