Windows GPU passthrough black screen on boot

Hello everyone,
I am attempting to have a windows HVM with my secondary nvidia GPU attached so that I can be able to use software like photoshop.

I’ve been following the github guide and almost everything seems to have worked.
GPU and its audio controller have been hidden successfully from dom0 and the grub config was regenerated again without troubles, qubes boots without problems and I got 2 cables running in my current monitor, one for my iGPU on which qubes runs and the other for my secondary GPU.
if I type lspci -vvn kernel in use for both GPU and audio device is pciback
I patched the 3.5G max ram succesfully too.

The problem now is that whenever I try to boot a windows VM with GPU passthrough it boots to a black screen for a while and the crashes, with qubes delivering this line as error:

Qube gpu_windows has failed to start: qrexec-daemon startup failed: xxxx-xx-xx qrexec-daemon[17818]: qrexec-daemon.c:135sigchld_parent_handler: Connection to the VM failed

This error doesn’t occur when the GPU isn’t attached, VM boots perfectly fine without it.

VM seems to boot up since I don’t get the ‘no bootable device’ error, it just boots to a black screen.
I tried letting the VM connect to the internet, maybe to let windows update do its job automatically but this just leads to the black screen staying on indefinitely until I kill the VM.

I did get the ‘no bootable device’ error for a while, but I didn’t get it anymore once I downgraded both xen-hvm-stubdom-linux and xen-hvm-stubdom-linux-full to versions 1.2.3 like someone said on this forum and on github.

anyone managed to get a windowsHVM to work with gpu passthrough?

wanted to write a little update: managed to get it working by lowering the initial memory lower than 3.5G…

I guess somehow the patch I tried to apply didn’t apply for some reason

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