Installing UC20 in Virtuabox triggers invalid signature after ubuntu-boot not found

snapd
10

So, as far as I understand from here, the idea for me is to modify the gadget.yaml and append this:

defaults:
  system:
    service:
      console-conf:
        disable: true

then using my model (which is this one) and adding the extra snaps the one i’ve just created, generate the image, right? Should I remove from my own model the pc-gadget, as i’m modifying the one that i’ve got from git? Also, should I change the grade of the model?

Thanks.