x86 PCs need insecure and ordinarily impossible to replace blobs in order to boot. It's true that PC firmware doesn't seem to hurt open source people's feelings quite so much as it once did, but there's not a ton of logic to that.
Unless things have changed significantly coreboot is an example of what I'm talking about - not a ton of x86 motherboard hardware is supported very well. "But for real openness, nothing beats an older x86 PC" just doesn't seem true at all.
(but I'll look into coreboot. I'd get a kick out of trying it.)
