Getting 8KX firmware 299 to work if multiple dedicated GPUs are connected

[sunny]

My desktop has two GPUs an AMD 550 (Slot 2) and an Nvidia 3090(Slot 1) for GPU passthrough.

I noticed that from firmware 299 on pitool 274 on the 8kx that the HMD is not connecting.
I checked with the technical support team, they reverted to firmware 296 I am able to get the HMD to display just fine on that firmware with pitool 271.

Is there a way to set a main GPU for pitool? I tried 3D settings in Nvidia control panel but they have long since removed the option to set a main GPU for an application.
I have my main displays set to the 3090 and disabled all displays on the 550 even tried unplugging all inputs connected to the 550GPU.
I tried changing the Main GPU in the bios to be slot 1 (3090) and reinstalled pitool and connected the HMD, no dice same issue.

The only way to get firmware 299 working is to either run w10 in a VM and passthrough a 3090 to it, or physically remove the 550 AMD GPU from the second slot.
The only way to get it working bare metal is the latter workaround which is just not practical, there is no way to disable a dedicated GPU in bios, and disabling the second GPU in device manager does nothing.

This used to work fine from firmware 296/ pitool 271 Is it possible for pimax/pitool software devs to fix this issue in a future firmware update?
Yvette from technical support team has my export logs.

[sunny]

The behaviour is odd, both the VM and the bare metal windows installs have the same pitool version, firmware version and Nvidia driver version installed (274, 299, and nvidia 497.29 UK respectively).

90HZ works on the VM, when I set it to 75Hz in the VM in pitool then reboot the PC to enter w10 in bare metal the headset displays static and shows as connected instead of disconnected.
In pitool it is set to 90Hz on bare metal, when I switch to 75hz there it works and boots into pimax home.
Now if I set to 90Hz again it will not connect.

Seems the only workaround to get the HMD to function with 299 with two dedicated GPUs is to set it to 75Hz. I hope this gets fixed, the very first beta with 90Hz used to work not sure why firmware 299/ pitool 274 doesn’t like you having multiple GPUs. would be nice if there was a setting in pitool to select a primary GPU.

[sunny]

I tried the latest Nvidia driver 511.23 as well same behaviour, I will revert to 296/271 and stick with 75hz for now I hope this gets resolved in a future update.

299 performance is abysmal, I suspect it is using the weaker GPU.