I want to switch back to the RPM version of GNOME Boxes because I can’t create new VMs using the flatpak version. I’ve tried doing what it said in the guide on switchting from RPM to flatpak but backwards, and it didn’t work.
I had to do this recently as well, and found this method to work for me:
Check where the flatpak VM images are stored - unless already using them at an external location, this should be at ~/.var/app/org.gnome.Boxes/data/gnome-boxes/images - move them out from this folder to where you’d like them to be.
Install gnome-boxes and virt-manager.
Using virt-manager, create a new VM and use the Manual mode to point it to the VM image copied in the first step. Repeat for each VM if you have multiple.
Close virt-manager and open GNOME Boxes. Now the non-flatpak version should show the VM.
Also note that:
You don’t technically have to move the VM images, but it’s a good idea since otherwise they’re in a folder that is tied to an uninstalled application.
This won’t copy anything unrelated to the images themselves, in case that matters.
Nonetheless, this worked well for me and I could then uninstall the flatpak version.