...

There are multiple RISC-V ports of xv6, including one for the Allwinner D1: https://github.com/michaelengel/xv6-d1

Zephyr

RISC-V Maintainers

• Karol Gugala (Antmicro)
• Tomasz Gorochowik (Antmicro)
• Filip Kokosinski (Antmicro)

Releases

Zephyr has supported RISC-V support has been present in the Zephyr RTOS since:

• v1.7.0, for RV32I (March 2017)
• v2.0.0, for RV64I (September 2019)
• v3.

...

• 2.0, for RV32E (September 2022)

RISC-V Status

As of February 2023, dozens of physical (non-emulated) targets are supported in Zephyr.

• List of RISC-V Boards: https://docs.zephyrproject.org/latest/boards/riscv/index.html
• Zephyr release notes: https://docs.zephyrproject.org/latest/releases/index.html