Hi Penguin,
We’ve recently released an official SiFive dev/platform where added support for HiFive1 Rev B. There are a lot of preconfigured examples.
Please note that you can experiment with SiFive IP Cores and RISC-V even without physical hardware using a built-in emulator. PIO Unified Debugger will work too! See a sample configuration:
[env:hifive1]
platform = sifive
board = hifive1
debug_tool = qemu
P.S: No need to install any toolchains, SDKs, Eclipse or etc. Everything works out of the box.