The root of the problem that old BIOSes wrote their configuration into the CMOS memory, while all UEFI-based firmware storing configuration right in the SPI fla

The root of the problem that old BIOSes wrote their configuration into the CMOS memory, while all UEFI-based firmware storing configuration right in the SPI flash itself. Changing the values of variables every boot, sometimes performing "garbage collection" for compressing the size. Moreover, ME-like systems also write into the flash, sometimes even logging events. Every single boot, this is how it was designed.