There's an opensparc 1000 running proprietary firmware, much like the Intel Management Engine and company. There's a small effort to replace that in open software. If I had oodles of free time I might contribute, but I've got my own projects to fry.
So, other than mangement engine firmware, that's a yes? We'll be able to turn it on and run 2d and 3d acceleration without closed-source blobs?
No, it has a Mali GPU, you still need a blob for that. The SoC doesn't have 2d hardware, unlike some older Allwinner chips.
You don't. Panfrost is already capable enough to run a simple desktop like Weston :)
Looks like Lima would be needed on the Pinebook, how well does that work ?
Not sure. Why is everyone talking about the original Pinebook now? The Pro is coming.