>> It is the shift key afaik. > For Grub Legacy, it most definitely is/was the ESC key. > http://www.gnu.org/software/grub/manual/html_node/Hidden-menu-interface.html#Hidden-menu-interface > I am fairly certain that still works with Grub 2. > That's not to say that Shift key doesn't work. I never tried it. For grub2, there is a "keystatus" entry in grub.cfg.