Comment # 2 on bug 1160478 from Takashi Iwai

Is this a regression by update or from previous version?
It looks like some BIOS thing that screwed up grub by some reason.

If the cold boot after shutdown works, try to pass some different value to
reboot kernel option.  See Documentation/admin/kernel-parameters.txt and
Documentation/x86/x86_64/boot-options.txt for brief descriptions.