BIOS includes some microcodes for supported processors, with proper util's u can mod BIOS files even for X99,Can you block microcode updates within the OS? With the BIOS, it is as simple as not updating beyond a certain version. My assumption is, with Linux, the microcode updates would be delivered through kernel updates. However, with Windows, my uneducated guess is that it would be packaged as a device driver update? And with the lovely W10 updates, your install will basically eat up whatever Microsoft decides to shit out and turn your working rig into a semi-brick until you can roll back the update.
Also, are the BIOS updates signed from the manufacturer, say ASRock, Speedmicro or Asus? Or can you flash a suitable binary without having to worry about signing or encryption?
but all motherboard vendors cook they're own soup.
the included microcodes are from intel only and encrypted with checksum.