Download Samsung Firmware SM-R866U
Samsung Galaxy Watch FE
The latest firmware for Samsung Galaxy Watch FE (SM-R866U) is R866USQS2BZG3 with Android 16, released on August 24, 2026 for 2 regions (CSC). Every official firmware build for SM-R866U, newest first: one row per build with all regions (CSC) that received it.
- Builds
- 9 builds
- Regions (CSC)
- 2 regions
Firmware builds for SM-R866U
- USCXAA
- XAA
- XAA
- XAA
- XAA
- XAA
- XAA
- XAA
- XAA
Each firmware build has its own page at https://samfirm.shop/build/{PDA}, where {PDA} is the build number from the list above. Example: https://samfirm.shop/build/R866USQS2BZG3
SM-R866U update history
SM-R866U started on Android 14 and has received 1 major Android upgrade; it now runs Android 16. The newest build, R866USQS2BZG3, was released on August 24, 2026 with the August 2026 security patch. That patch (SMR Aug-2026) fixes 54 vulnerabilities, 8 of them critical. Over the last 12 months SM-R866U received 5 builds, spread over 4 different months.
Changelog for SM-R866U
• Security
The device is protected with improved security.
These changes may vary depending on the model, country, or network operator of the customer environment.
- R866USQS2BZG3Aug 24, 2026
- R866USQS2BZE1Jun 23, 2026
• Stability and reliability
Device behavior has been improved.
• Security
The device is protected with improved security.
These changes may vary depending on the model, country, or network operator of the customer environment.
• Security
The device is protected with improved security.
These changes may vary depending on the model, country, or network operator of the customer environment.
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• Security
The device is protected with improved security.
These changes may vary depending on the model, country, or network operator of the customer environment.
Show 2 older builds
• Security
The device is protected with improved security.
• Stability and reliability
The stability has been improved.
• Security
The device is protected with improved security.
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Frequently Asked Questions
What is the latest Android version for SM-R866U?
The newest firmware for SM-R866U runs Android 16: build R866USQS2BZG3, released on August 24, 2026.
When did SM-R866U get its last update?
The latest build for SM-R866U, R866USQS2BZG3, was released on August 24, 2026 (2 months ago).
How often does SM-R866U get updates?
Over the last 12 months SM-R866U received 5 builds, with at least one new build in 4 different months.
Is the firmware for SM-R866U official?
Yes, all firmware files for SM-R866U are 100% official, original, and obtained directly from Samsung servers.
How to flash Samsung SM-R866U using Odin?
To flash SM-R866U, you need to download the appropriate firmware, put your device into Download Mode, and use the Odin tool to load the BL, AP, CP, and CSC files.
Can I downgrade the Android version on SM-R866U?
Downgrading is only possible if the bootloader version (binary bit) of the old firmware matches the current one. Always check the binary version before flashing SM-R866U.