I managed to trace the source of this issue, at least in my case, to a missing package "mokutil". Installing this automatically ran the postinst script again and it now works fine. Hopefully this will help someone else.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1860491 Title: package grub-efi-amd64-signed 1.128.1+2.04-1ubuntu12.1 failed to install/upgrade: installed grub-efi-amd64-signed package post- installation script subprocess returned error exit status 127 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub2-signed/+bug/1860491/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
