The attached patch fixes the problem for me. I'll try and upstream it, though a pure upstream build is crashing elsewhere for me at the moment.
** Patch added: "progress-check-filename-for-NULL.patch" https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1459872/+attachment/4442954/+files/progress-check-filename-for-NULL.patch -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1459872 Title: arm64 images built w/ the progress module crash GRUB To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1459872/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs