I already use UEFItool to extract the menu and I got this setup.txt
and after looking at relative entries in the txt, I suppose that I have to change this three entries default value:
One Of: CPU PCIe Lanes Configuration, VarStoreInfo (VarOffset/VarName): 0xC9F, VarStore: 0x1, QuestionId: 0xF27, Size: 1, Min: 0x0, Max 0x3, Step: 0x0 {05 91 24 30 25 30 27 0F 01 00 9F 0C 10 10 00 03 00}
One Of: Support PEG Bifurcation Card, VarStoreInfo (VarOffset/VarName): 0x67B, VarStore: 0x1, QuestionId: 0x2AC, Size: 1, Min: 0x0, Max 0x1, Step: 0x0 {05 91 4C 1F 4D 1F AC 02 01 00 7B 06 10 10 00 01 00}
One Of: CFG Lock, VarStoreInfo (VarOffset/VarName): 0x3E, VarStore: 0x11, QuestionId: 0x11B3, Size: 1, Min: 0x0, Max 0x1, Step: 0x0 {05 91 DF 01 E0 01 B3 11 11 00 3E 00 10 10 00 01 00}
I use RU to change their value, though the computer boot, nothing happened, the second pcie card on my 8x+8x bifurcation riser card just not showing up.
Does anyone has any idea how to solve this? or maybe I should just switch to other brands as they support bifurcation out of box, but I don't bother buying another z490i board as Alder lake is coming.