Wii games wouldn't load on Wii U vWii using two disk setup

[pankosoknap]

Any attempt to load Wii games would always kick me back to loader.

My setup is:
Wii U vWii
WiiU HDD plugged in top back USB port.
vWii HDD plugged in bottom back USB port. There are two partitions on HDD: FAT32 and NTFS partition, MBR.
cIOS forced to 251. This is the only one, where my vWii HDD is properly initialised in Wiiflow and USBLoaderGX. Wii games are showing fine in catalogue. Cache reloaded.
I have cIOSs installed:

d2x-v11-beta1-vWii, base: 56, slot: 249
d2x-v11-beta1-vWii, base: 57, slot: 250
d2x-v11-beta1-vWii, base: 58, slot: 251

All other stuff such as GC games and plugins are running fine on this setup.

The problem present only when Wii U HDD is connected. As soon as I disconnect Wii U HDD Wii games start to load just fine.

I have tried to load Wiiflow from SD card and USB FAT32 partition.

USBLoaderGX is able to run WIi games just fine on the same setup.

I can't swap HDDs because they would not be recognised in vWii HBC in other setup.