@lfb6 - You’re welcome! MMTool for PEI ucode edit is much easier and safer 
I can’t remember if FF or 00 better for this PEI maintain spacing during that kind of mod, it may differ between BIOS versions/brands, etc too, so probably best to just do these with MMTool when you run into them
@Captain_Caverne - You cannot flash mod BIOS with EZ Flash, except in rare instances. See here for possible ways to flash your mod BIOS - [Guide] How to flash a modded AMI UEFI BIOS
Actually, your board has USB Flashback and file must be in properly signed capsule named Z9PED8WS.CAP, that is how you should flash mod BIOS on the Z9PE-D8-WS board
Google and you will find videos, and read your manual too so you know which port to use.