What is the output of apt-cache policy grub-pc, and apt-cache policy grub-efi-amd64? If you don't have an /etc/default/grub file at all, it sounds like you do not have grub installed and have Debian installed on another partition and that is what is booting your system.
** Changed in: grub2 (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1597382 Title: grub2 os selections screen changed after today's updates To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1597382/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs