ME firmware is on the same SPI flash part as the host firmware[0] The BIOS doesn't need to load the ME firmware - that wouldn't be very useful since the ME is

ME firmware is on the same SPI flash part as the host firmware[0] The BIOS doesn't need to load the ME firmware - that wouldn't be very useful since the ME is what gets the CPU out of reset these days. However, there are more binary components on a contemporary Intel device (listing the variants used with coreboot. other firmware may look slightly different, but the parts are pretty much the same internally): CPU microcode updates (useful because they can't manage to ship CPUs that work correctly on the first try); FSP (memory initialization code that's totally boring but guarded like a state secret); graphics initialization code (VGA BIOS or GOP driver. likewise boring-but-secret); sometimes some more hardware initialization, but we try to get most of that opened up (with varying success). And then there are some more signed binary components that aren't directly related to host firmware: TXT and SGX require intel-signed code, and - newest addition, I think - GPU firmware binaries. Because they were so well received with AMD and nVidia hardware. source: am a coreboot developer. [0] It's also a NOR part, not NAND, and it may be multiple SPI devices that the firmware hub exposes like a single one, but either detail is beyond nit-picking for the current discussion.