This stuff is certainly pretty rarified these days. I remember when the PPC970 came out people were shocked how difficult it was to bootstrap. IBM didn't really care as POWER4 (from which it was derived) was not a merchant chip and they had management processors (and very high margins) in all their machines to handle it. Apple was the launch partner and even back then had a lot of in house expertise doing this sort of work. Everyone else who tried to use it was in for some real pain and most of them gave up. The guys doing the eval boards with support from IBM literally posted this: https://web.archive.org/web/20060715134515/http://www.970eva...

TL;DR, the last line is "Once all of the above is completed, the processor will be able to successfully fetch instructions from a boot source. You are now effectively at the same point you would have been 5 months ago, had this been a standard 750 bringup... Board bringup from this point should be very straightforward and follow established methods."