No official images, no. I have a personal one: https://github.com/queenkjuul/milkv-duo-ubuntu

But it isn't generalized.

It also doesn't support the weird sophgo "media engine" which is the big roadblock, but the code might help you.

There's been updates since i published that, though.

There is someone out there with an open source bootloader blob, i think i saw it on the milk-v forums can't remember the link