New comment by phrdina on void-packages repository

https://github.com/void-linux/void-packages/issues/23495#issuecomment-662440938

Comment:
@pandom79 No it doesn't depend on the ISO file. It depends on the selected or detected OS that you are installing inside the VM.
If you pick windows or it is detected it will pick Q35 as default machine type using osinfo project and virt-manager will get domain capabilities only for Q35 machine type which will contain secure boot firmware and non-secure boot firmware.

If the selected or detected OS will lead to i440FX it will contain only non-secure boot firmware.

The situation that you describe is not working correctly because if you change the machine type into i440FX the secure boot firmware should disappear as it will not work with i440FX.