I checked the grub2's source code, command clear will invoke each output backend's cls method, and it seems that the black rectangle is produced by backend "console".
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1308723 Title: clear, after background_color command uses a black color and thus only colors a frame To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1308723/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs