AMI MMtool 4.xx, UEFI tool or HEX editor.
Old mcodes here: [OFFER] Intel CPU Microcode Archives - Special Topics / CPU Microcodes - Win-Raid Forum (level1techs.com)
You do know that the windows mcode will supersede the mcodes on bios…
If you want to use the BIOS intel microcode you must delete/rename from the following file:
C:\Windows\System32 - mcupdate_GenuineIntel.dll