(replying to parent as well). I have not used it but zephyr (https://www.zephyrproject.org https://www.zephyrproject.org) is a cross platform (including riscv)

(replying to parent as well). I have not used it but zephyr (https://www.zephyrproject.org https://www.zephyrproject.org) is a cross platform (including riscv) os/platform that looks interesting for embedded development.