> AFAIK the microcode updates aren't mandatory, you can use your computer without them and use the stock microcode (though that's also proprietary).
Microcode is only one part of it. I was thinking of the ME firmware, and to a lesser extent the FSP. It's not possible to boot a modern Intel processor without ME. The ME has direct DMA access to all peripherals and can use the network interfaces directly, behind the operating systems back.
I believe AMD has similar things. They are all signed by the manufacturer and the hardware will refuse to load a replacement even if it existed.
Puri.sm has been saying for weeks they are going to have a big announcement about the ME "next week". I do wish their process was a bit more open, but I'm hoping they've actually found a way to make the machine boot without an ME. That in and of itself would be a huge step forward for libreboot/coreboot.
