Re: 'error: invalid signature' when booting Windows 10

[Pascal Hambourg]

Le 13/12/2018 à 21:53, David Collier a écrit :
> On Thu, Dec 13, 2018 at 11:52 AM Pascal Hambourg <address@hidden>
> wrote:
>
> > Le 13/12/2018 à 07:49, David Collier a écrit :
> >
> > You must install GRUB EFI for the architecture matching your UEFI
> > firmware (32 or 64 bits, most likely 64 bits - NOT the CPU
> > architecture), but grub-install will be able to register an EFI boot
> > entry for itself only if the system was booted in EFI mode.
>
>
> I can't say I understand this. You mean it would start showing up as yet
> another boot option in the BIOS dialogue?

Yes. And it should have the highest priority so that the firmware 
selects it for booting.

> How do I install GRUB EFI?

First, you install the packages which provides the commands and files 
needed to install GRUB EFI. Then you run grub-install with the proper 
arguments.

> > What is the installed distribution ?
>
> it's Debian
>
> DISTRIB_DESCRIPTION="Linux Mint 19 Tara"

Linux Mint is not Debian. It is based on Ubuntu, which is not Debian 
either. There is a flavour or Mint which is based on Debian, labelled 
LMDE for "Linux Mint Debian Edition". All these distributions just share 
Debian's packaging system.

In Debian the 64-bit GRUB EFI package is grub-efi-amd64 and the 32-bit 
GRUB EFI package is grub-efi-ia32.

> > The installer of some distributions provide a
> > rescue mode which allows to chroot the installed system. Also you can
> > boot a live system in EFI mode and run grub-install from there using the
> > proper --boot-directory and --efi-directory options. Or you can boot the
> > installed system in EFI mode with something like GRUB Rescue.
>
> so, I can boot from the USB stick with the Debian distribution and chroot
> into the installed system, what do I do next?

The Debian installer has a rescue mode, but I don't know if Mint's 
installed does. IIRC it is based on Ubuntu's installer, which is very 
different from Debian's.

After you have chrooted into the installed system, you mount the EFI 
partition and just run grub-install without parameters.

> How do I force BIOS to boot from the USB stick in one mode vs another?

This is specific to each UEFI firmware implementation.
A prerequisite is that the USB stick is set up for EFI boot. You can see 
it if it contains a FAT partition containing EFI/BOOT/BOOTX64.EFI for 
64-bit EFI or EFI/BOOT/BOOTIA32.EFI for 32-bit EFI.