Given we've been doing work on qemu and linux-kernel we started looking at u-boot too. I've done a quick test with our qemu and got a few patches going.
It looks like there are only a few updates to get the build working. The only question I have at the moment is with the read/write io macros which seem to be incosistently endian interested. project at: https://gitlab.com/CodethinkLabs/riscv_bigendian
