Sorry for the delay in responding.
My understanding is that if the bios chip is in a High Impedance mode, then one can reflash the bios or read the bios by using a SPI programmer along with a eight pin clamp on the bios.
If the chip is in a high impedance state any external changes to it would not be affected by the MB circuits.
Otherwise to read or update the bios, the chip needs to be removed from the MB in order to read or reflash it.
I was thinking about modifying the bios so that it could boot from a Nvme. Do a search for Fernando's Win-Raid Forum, if you are interested.
Since Intel didn't release any Spectre/Meldown patches for my MB, I have decided to move to a new MB.