Bootlin has been maintaining Freedom-U-SDK (FUSDK), a Yocto/OpenEmbedded-based software development kit for RISC-V platforms from SiFive, in collaboration with SiFive since 2022.
The Yocto support for SiFive RISC-V platforms is split into two layers:
- meta-sifive, a BSP layer providing
machine-specific support - freedom-u-sdk, a demo and SDK layer that builds images for the HiFive Unmatched board and QEMU RISC-V 64-bit targets
In a previous blog post we summarized the work done up to the 2022.10 release. This new post covers everything since then, up to the latest 2026.07.00-lts release which was published recently.
2022
The 2022.12 release added virtualization support to the images. Toolchain and platform components received only minor updates: LLVM 15.0.3 → 15.0.4, Mesa 22.2.0 → 22.2.2, Linux kernel 5.18 → 5.19, and U-Boot moved to the 2022.10 release.
2023
Five releases shipped across 2023, marked by a major kernel LTS migration and substantial toolchain progress:
- Toolchain: GCC 12.2 → 13.2, LLVM 15.0 → 17.0, Glibc 2.36 → 2.38, Binutils 2.39 → 2.41, GDB 12.1 → 13.2
- Graphics: Mesa progressed through the 22.x and 23.x series, reaching 23.2.1
- Kernel and platform: the 2023.02 release migrated from Linux 5.19 to the 6.1 LTS branch (6.1.8 → 6.1.61 by year-end); Linux headers updated to 6.5; OpenSBI 1.1 → 1.3.1; U-Boot 2022.10 → 2023.10
- Notable fix: the 2023.10.01 patch release reduced DDR speed to 1600 MT/s to address stability issues on the Unmatched board
2024
Another five releases in 2024, with a second kernel LTS switch and further toolchain jumps:
- Toolchain: GCC 13.2 → 14.2, LLVM 17.0 → 19.1, Glibc 2.38 → 2.40, Binutils 2.41 → 2.43.1, GDB 13.2 → 15.2
- Graphics and Python: Mesa reached 24.0.7; Python3 version tracking was added to the release notes from 2024.03, moving from 3.11.5 to 3.13.0 by year-end
- Kernel and platform: the 2024.01 release switched to the 6.6 LTS branch (6.6.12 → 6.6.59); Linux headers reached 6.12; OpenSBI 1.4 → 1.6; U-Boot 2024.01 → 2024.10
2025
Two releases shipped in 2025:
- 2025.02: switched the longterm kernel from the 6.6 LTS branch to the 6.12 LTS branch; GDB 15.2 → 16.2, Glibc 2.40 → 2.41, Binutils 2.43.1 → 2.44, U-Boot 2024.10 → 2025.01
- 2025.10: updated layers to the Walnascar Yocto Project release; LLVM 19.1 → 20.1, GCC minor update to 14.3.0; Xfce4 4.20 desktop environment explicitly tracked in the release notes from this point onwards
2026
Two releases have shipped in 2026 so far:
- 2026.01: aligned layers with the Whinlatter Yocto Project release; GCC 14 → 15.2, LLVM 20 → 21.1, Glibc 2.41 → 2.42, Binutils 2.44 → 2.45, GDB 16.2 → 16.3; Linux kernel migrated to the 6.18 branch; OpenSBI 1.6 → 1.8.1; Mesa 24.0.7 → 25.2.5
- 2026.07.00-lts: updated layers to the Wrynose Yocto Project release; LLVM 21.1 → 22.1.3, Glibc 2.42 → 2.43, Binutils 2.45 → 2.46, GDB 16.3 → 17.1, Mesa 25.2 → 26.0.5, Python3 3.13 → 3.14.4; Linux headers updated from 6.17 to 6.18
All releases are available on the Freedom-U-SDK GitHub repository.
The latest release can be found under the 2026.07.00-lts tag.
Bootlin will continue to maintain and improve the BSP and FUSDK for SiFive platforms, keeping the layers up to date with the latest OpenEmbedded releases, tracking upstream toolchain and kernel progress, and addressing bugs and security issues as they arise.
