> I can't take any other measurement they published seriously.
Here's another problem with the article:
> Microsoft is pushing out OS-level updates [...] However, this doesn’t mitigate the problem entirely, for that we need motherboard BIOS updates and reportedly Intel has released the new microcode to motherboard partners. However as of writing no new BIOS revisions have been released to the public.
That's wrong - microcode updates can be successfully applied by either the OS or by the early-boot firmware, you do not need a BIOS update (just apt update intel-microcode).
No. I have to look it up to be certain but I believe that MS did not want to patch CPU microcode during boot and tried to leave that to the firmware. But - I may be wrong here - this stance changed with Spectre and Meltdown and Windows does indeed patch microcode during boot on affected CPUs. However, I don't think there is a way to apply a user-specified patch. The update has to come from MS.
Microcode is stored in volatile memory on the CPU. Updates are applied on boot, every boot. "Downgrading" is as simple as not applying updates, or applying an older update.
Loading microcode on a CPU (without patching the firmware) takes effect immediately. The update is lost immediately upon reboot and must be reapplied each time.
Here's another problem with the article:
> Microsoft is pushing out OS-level updates [...] However, this doesn’t mitigate the problem entirely, for that we need motherboard BIOS updates and reportedly Intel has released the new microcode to motherboard partners. However as of writing no new BIOS revisions have been released to the public.
That's wrong - microcode updates can be successfully applied by either the OS or by the early-boot firmware, you do not need a BIOS update (just apt update intel-microcode).