In documents from other distributions there is a OVMF_CODE.secboot.fd but I can only find a OVMF_CODE.fd. Finally I just use OVMF_CODE.secboot.fd and OVMF_VARS.ms.fd from debian and everything just works. What’s the recommanded method to do this? Something like the debian packages which works out of the box is helpful.
I don’t know how they’re registered in virt-manager, but in any case you should be able to edit the libvirt xml directly. Use your OVMF workaround to see what the xml should look like if necessary.
You can edit the xml file in virt-manager or gnome boxes.
I didn’t use the OVMF from NixOS. It doesn’t work for me. I guess it’s not signed by Microsoft. The files from CentOS works for me. You can get them from CentOS Mirror, search the edk2-ovmf.