Bug#902928: Cannot bring the grub menu up with Shift key along with GRUB_TIMEOUT_STYLE=hidden with GRUB_TIMEOUT=0

[Colin Watson]

On Tue, Jul 03, 2018 at 06:14:14PM +0200, Yuri D'Elia wrote:
> I was using grub-pc until recently, where I migrated to grub-efi-amd64.
> It's the same hardware (lenovo yoga x1).
> 
> My grub configuration is unchanged, and consists of:
> 
> GRUB_TIMEOUT=0
> GRUB_TIMEOUT_STYLE=hidden
> 
> I was used to hold shift during boot to bring the grub menu up during
> boot, which worked flawlessy.
> 
> With grub-efi-amd64 it doesn't work anymore.

When I last looked into this, this wasn't possible with UEFI: the
firmware doesn't tell us about held modifier keys.  You'll probably need
to use a short but non-zero timeout and press Escape instead.

(It's possible that more recent versions of the UEFI spec have improved
this; but if so then somebody would need to implement that in GRUB, and
it would still only work if you had new enough firmware.)

-- 
Colin Watson                                       [cjwatson at debian.org]