You didn't remove all the 177 packages, the headers package or so pulls in a kernel and then apt switches to the unsigned one.
I'm going to reassign this to Linux, as we should ensure that doesn't happen by not allowing unsigned to satisfy those dependencies. ** Package changed: grub2-signed (Ubuntu) => linux (Ubuntu) ** Changed in: linux (Ubuntu) Status: Invalid => New ** Summary changed: - upgrade from 18.04 to 20.04 while on rollbacked kernel 4.15-0-177 - package grub-efi-amd64-signed 1.167.2+2.04-1ubuntu44.2 failed to install/upgrade: installed grub-efi-amd64-signed package post-installation script subprocess returned error exit status 1 + Removing signed kernel installs unsigned one due to dependencies -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1975388 Title: Removing signed kernel installs unsigned one due to dependencies To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1975388/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs