PINE64

https://fydeos.com/download/

I think fyde os would be a great OS for the pinebook.

Linux, Android compatible, and liGNUx compatible via LXC.

But I did not find images.

Also it would be funny that the Pinephone that shares SoC with the pinebook would be the first smartphone capable of running Chromium OS too.

I would likely need to be built from source, as they don't have an image for any A64 hardware. I can't find any reference of Chromium OS running on that hardware, either. It would be nice, though I agree.

If you want something now, the /e/ Android image for the Pinebook is very stable and works well. (Though I haven't had a chance to test the updated image posted, yet.)