I believe this comment might provide a workaround to the "no access to GRUB options" problem:
https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1273764/comments/8
It's about another bug in which grub ignores the timeout options in /etc/default/grub
I believe this comment might provide a workaround to the "no access to GRUB options" problem:
https:/ /bugs.launchpad .net/ubuntu/ +source/ grub2/+ bug/1273764/ comments/ 8
It's about another bug in which grub ignores the timeout options in /etc/default/grub