Thanks for the advice ijohnson.
I’ll try that too. At least I got it running, but I had to include the wget package and override-stage section of shim-signed_1.43+uc20.4+15+1552672080.a4a1fbe-0ubuntu2_amd64.deb, since it was impossible to me to get it working without it, unable to find the shim-dualsigned , just like the issue in the link ogra provided, using the pc-amd64-gadget snap, (i’m building it from a ubuntu desktop 20.04 os, maybe that’s what is wrong here?).