Samsung Galaxy S25 (SM-S931B) Firmware Overview
What is the latest SM-S931B firmware?
S931BXXSDDZJ1, released October 9, 2026 for region CGU with Android 17. It is a security update on bootloader binary 13. The archive holds 4 official builds for this region. Each one is the full stock ROM (flash file) for Odin, not an OTA patch.
Is the Samsung Galaxy S25 still getting updates?
Yes. The newest build is from October 2026.
Which Android versions did it get?
The SM-S931B builds in the archive run Android 16 to 17. The earliest build we have for each version:
- Android 17: S931BXXSDDZJ1 (Oct 2026), 1 build in total
- Android 16: S931BXXU9CZDP (May 2026), 3 builds in total
Can I downgrade the SM-S931B firmware?
Only to builds with the same bootloader binary (the Bit column) or higher. In the archive the binary of this model rose from 9 to 13:
- Binary 13 — since Oct 2026
- Binary 12 — since Aug 2026
- Binary 11 — since Jul 2026
- Binary 9 — since Apr 2026
A phone already on binary 13 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 13 build. How to read a build number.
SM-S931B firmware for region CGU
How to Flash SM-S931B Firmware
Put the Samsung Galaxy S25 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 13 or higher if your phone is already on the latest firmware. Use HOME_CSC to keep your data, CSC for a full wipe.