M558BXXS3CZB4 – Galaxy M55s 5G firmware
Build M558BXXS3CZB4 is a security update for the Galaxy M55s 5G (SM-M558B)
on Android 16 (One UI 8). It first appeared on Samsung's servers on Mar 10, 2026 (method) and has reached
1 region so far. It raises the bootloader bit from 2 to 3: once installed, the device no longer accepts firmware with bit 2 or lower, so a downgrade to M558BXXS2CYL1 is blocked. Samsung still serves this file.
- Model
- SM-M558B
- Android
- Android 16
- Type
- Security
- Bootloader bit
- 3
- First released
- Mar 10, 2026
- Regions
- 1
Rollout timeline by region
The date each region code (CSC) first received M558BXXS3CZB4, counted from the first release.
| CSC | Region | Released | Rollout | Version (PDA/CSC/MODEM) |
|---|---|---|---|---|
INS | India | Mar 10, 2026 | day 0 | M558BXXS3CZB4/M558BODM3CZB4/M558BXXS3CZB4 |
Download and release notes
samloader download -m SM-M558B -r INS -v M558BXXS3CZB4/M558BODM3CZB4/M558BXXS3CZB4Samsung's release notes and security patch level for this update: SM-M558B / INS on doc.samsungmobile.com. What each part of the build number means: decode M558BXXS3CZB4.