I don't know enough about it. If I understand correctly, the RISC-V instruction set architecture is free/libre but that is separate from particular implementations, meaning actual chips and their designs. I don't know enough about how that distinction plays out or which manufacturers produce free/libre stuff and which don't. I would look at https://libreboot.org/news/policy.html to try to learn more. Somehow I recall hearing about very large and proprietary binary blobs used to boot RISC-V but I cannot quickly find it. So maybe it's fine, maybe not.