I dunno, this write-up both seems a lot more detailed than Wikipedia re: the hypervisor & kernel and agrees with my recollection as foolishly confirmed by an LLM:

https://www.copetti.org/writings/consoles/xbox-360/#operatin...

Appreciatively discussed on hn!

https://news.ycombinator.com/item?id=31678045

Doesn’t sound at all like the NT/2000 kernel/HAL/Executive.