if keystatus -s ; then timeout=10 else boot
Note: Make sure to put that
fi, on its own line(like above), under the rest; before issuing the commands below:
sudo config grub-mkconfig -o /boot/grub/grub.cfg
sudo update-grub (...can't hurt)
Make sure you get no errors.
It works; when I hold down Left, or Right shift; before leaving my computers (an HP desktop) BIOS post screen. So, is the first thing GRUB2 "sees".
There are still reports of some computers not working. I'd try this. Best wishes.
FYI: I'm on Debian 7 (Wheezy, and with my added Mate, only.)
I have LightDM installed, and text configured to autologin.
After post, and before this GRUB2 start, I'm 33 seconds to my Mate desktop; without further optimizing.