Samus booting into U-Boot both from coreboot and bare metal (left). Lots of binary blobs still. For some reason I have found x86 quite intriguing. One of the many intrigues is the MTRR registers, which control cacheability and write-combining, but are quite separate from the page tables. Another is that it takes 7 seconds just to set up the memory controller. Yes you read that right. A normal Chromebook can boot into Linux in that time.
Intel's documentation is really good compared to most vendors IMO. I've heard people complain about it but they really need to get out more.
However the layers of complexity boggle the mind. Hundreds upon hundreds of MSR registers, the RCB, the MCH, microcode loading, binary blobs for video and 'management' and the PCH and setting up memory, the symbiotic relationship between firmware and kernel. It's all there. Perhaps I need to get back into the relatively straightforward ARM world?
Working on it...