G991USQSFHYE2 – Galaxy S21 5G firmware
Build G991USQSFHYE2 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 4, 2025 (method) and has reached
8 regions so far. It raises the bootloader bit from 14 to 15: once installed, the device no longer accepts firmware with bit 14 or lower, so a downgrade to G991USQUEHYDA is blocked. Samsung still serves this file.
- Model
- SM-G991U
- Android
- Android 15
- Type
- Security
- Bootloader bit
- 15
- First released
- Jun 4, 2025
- Regions
- 8
Rollout timeline by region
The date each region code (CSC) first received G991USQSFHYE2, counted from the first release.
| CSC | Region | Released | Rollout | Version (PDA/CSC/MODEM) |
|---|---|---|---|---|
SPR | USA (Sprint) | Jun 4, 2025 | day 0 | G991USQSFHYE2/G991UOYNFHYE2/G991USQSFHYE2 |
TMB | USA (T-Mobile) | Jun 4, 2025 | day 0 | G991USQSFHYE2/G991UOYNFHYE2/G991USQSFHYE2 |
CCT | USA (Comcast) | Jun 4, 2025 | day 0 | G991USQSFHYE2/G991UOYNFHYE2/G991USQSFHYE2 |
VZW | USA (Verizon) | Jun 4, 2025 | day 0 | G991USQSFHYE2/G991UOYNFHYE2/G991USQSFHYE2 |
DSH | USA | Jun 5, 2025 | +1 day | G991USQSFHYE2/G991UOYNFHYE2/G991USQSFHYE2 |
DSA | USA | Jun 5, 2025 | +1 day | G991USQSFHYE2/G991UOYNFHYE2/G991USQSFHYE2 |
ATT | USA (AT&T) | Jun 8, 2025 | +4 days | G991USQSFHYE2/G991UOYNFHYE2/G991USQSFHYE2 |
USC | USA (US Cellular) | Jun 10, 2025 | +6 days | G991USQSFHYE2/G991UOYNFHYE2/G991USQSFHYE2 |
Download and release notes
samloader download -m SM-G991U -r SPR -v G991USQSFHYE2/G991UOYNFHYE2/G991USQSFHYE2
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 G991USQSFHYE2.