Just a necrobump to advise that i was not able to get this working even running a Xeon 1650 V4 with all 40 pcie lanes on the same motherboard
I’ve been able to get bifurcation working on Asus X99 Deluxe2 via RU.exe mode of registers directly but was not able to get any BIOS mod to work, tried various combinations of IOU0 to IOU4 in 4x4x4x4x but something doesn’t seem to be taking
I used this BIOS to get it to work, but I have 2 PCIe boards with 2 x 4 NVME’s and only see 5 NVME’s not all 8. Not sure if you want to see only 4 and have the Asus X99 Deluxe II, then this will work.
EDIT, I have it working with GFX card and another NVME in another slot, I can see 6 NVME’s one being my boot drive see my post here.