M566BXXS4BYK2 – Galaxy M56 5G firmware
Build M566BXXS4BYK2 is a security update for the Galaxy M56 5G (SM-M566B)
on Android 16 (One UI 8). It first appeared on Samsung's servers on Nov 17, 2025 (method) and has reached
1 region so far. It raises the bootloader bit from 3 to 4: once installed, the device no longer accepts firmware with bit 3 or lower, so a downgrade to M566BXXU3BYI6 is blocked. Samsung still serves this file.
- Model
- SM-M566B
- Android
- Android 16
- Type
- Security
- Bootloader bit
- 4
- First released
- Nov 17, 2025
- Regions
- 1
Rollout timeline by region
The date each region code (CSC) first received M566BXXS4BYK2, counted from the first release.
| CSC | Region | Released | Rollout | Version (PDA/CSC/MODEM) |
|---|---|---|---|---|
INS | India | Nov 17, 2025 | day 0 | M566BXXS4BYK2/M566BODM4BYK2/M566BXXS4BYK2 |
Download and release notes
samloader download -m SM-M566B -r INS -v M566BXXS4BYK2/M566BODM4BYK2/M566BXXS4BYK2Samsung's release notes and security patch level for this update: SM-M566B / INS on doc.samsungmobile.com. What each part of the build number means: decode M566BXXS4BYK2.