Huananzhi x79-8d bifurcation trouble

Even though it is obvious the AMI BIOS of this chinese mobo has some kind of PCIE3.0 bifurcation support. I tried inserting a x16 bifurcation card with 4xNVMe (WD SN570) and
it showed only 1 NVMe (“Sandisk Corp WD Blue SN570 NVMe SSD”) when mobo bifurcation was at x16,

and when mobo bifurcation was set to x4x4x4x4, only 1 “Sandisk Corp Device 501a” came out. Help or pointers needed.

I had tried the above bifurcation card on another mobo of mine (Supermicro x9srl) on a PCIe slot x16physical x8eletrical and indeed in OS I could see 2 NVMe’s showed up ready.

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NUMA = enable
IOH0 IOH1
x8 x8
x16 x16
x16 x16
 
# lspci -vt
 
\-[0000:00]-+-00.0 Intel Corporation Xeon E7 v2/Xeon E5 v2/Core i7 DMI2
+-01.0-[01]----00.0 Sandisk Corp WD Black 2018/SN750 / PC SN720 NVMe SSD
+-02.0-[02]----00.0 Sandisk Corp WD Blue SN570 NVMe SSD
+-03.0-[03]--
 
case:
NUMA = enable
IOH0 IOH1
x4x4 x4x4
x4x4x4x4 x4x4x4x4
x4x4x4x4 x16 (for nvidia graphic card support)
 
\-[0000:00]-+-00.0 Intel Corporation Xeon E7 v2/Xeon E5 v2/Core i7 DMI2
+-01.0-[01]----00.0 Sandisk Corp WD Black 2018/SN750 / PC SN720 NVMe SSD
+-01.1-[02]--
+-02.0-[03]----00.0 Sandisk Corp Device 501a
+-03.0-[04]--
 
 


I tried to attach the .rom file of my mobo but this forum would not allow me to.