Hugo MillsNew blog post: How U-Boot boots.
I dug into it so you don't have to.
Also, I didn't put it in the blog post, but the #UBoot docs are *really hard* to use. They're badly fragmented. There's little to no flow of concepts or overview. There are examples with no explanation. There are examples without links to the things they use. The stuff that I was looking for, which I'd have expected to be under "Use U-Boot" was actually hidden away in a section with a nondescript name in the "Develop" section. Everything's *searchable*, but nothing's *discoverable*.
I eventually found what I was looking for in a wiki post from someone at Xilinx, who gave me enough information and keywords to track down the details of the process I needed to know. That was after a week or so of fruitless web searching, including reading through large swathes of the U-Boot docs.