Not sure if Dell BIOS could be modded though.... not too much info on the web about this topic.... >_<
Dell BIOS is cryptographical signed/protected. without re-sign after mod. it will not work.It sounds like it might be possible to patch 2.3.1 with the older microcode?
the latest microcode is loaded later by the OS (Windows or Linux)
doubt that. ASRock Rack usualy do not provide actual MCU on BIOS but support DCPMM.However I don't know if newer microcode is necessary for Optane DCPMM support.