There aren't even any arm or x86 desktops that are completely blob free. There is some ridiculously expensive amd power hungry power9 thing that nothing will run on, and some of sifive's newer boards might qualify. Every arm at least has some soc blobs. And every x86 has something like ime. Going straight for a blob free phone seems like getting ahead of ourselves. How about we shoot for a completely free rpi usable on the desktop first?
It os definitely more open than most, thanks! I'm pretty sure it still has the masked boot rom before getting to the open bits. While the tpl and ddr are still blobs and might harbor naughtiness, people have at least figured out how to edit the blobs https://github.com/hbiyik/rkddr
U-boot for Rockchip builds it's own TPL. I'm using it right now. It can also use Rockchip's TPL, but that's optional, not the default. DDR training code is here: