This is a recent apt history log. Perhaps it may provide an extra clue to the cause. The boot failure began after the December 9 update.
** Attachment added: "hp15-ay016nr_apt_history.log" https://bugs.launchpad.net/ubuntu/+source/gdm3/+bug/1808125/+attachment/5221866/+files/hp15-ay016nr_apt_history.log -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1808125 Title: [WORKAROUND] Ubuntu 18.10 boot hangs with INTEL GRAPHICS at msg "Starting bpfilter" To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gdm3/+bug/1808125/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs