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

[Pascal Hambourg]

Le 10/12/2018 à 22:59, David Collier a écrit :
> On Mon, Dec 10, 2018 at 1:47 PM Pascal Hambourg <address@hidden>
> wrote:
>
> > Le 09/12/2018 à 22:04, David Collier a écrit :
> > > I am trying to retire an old HD where grub /boot directory happens to
> > > reside, so I am trying to move it to the current Linux root partition
> > which
> > > is on an SSD.
> >
> > Did you move/reinstall a new GRUB in an EFI partition on the SSD too ?
>
> I copied the script below to the SSD /etc/grub.d  directory and ran
> update-grub, and verified that the menu shown when booting comes from this
> grub instance.

This is not what I am asking for. What about the GRUB bootloader itself 
(boot image and core image) ? Did you run grub-install ?

> > For now, the only explanation which comes to my mind is that the active
> > GRUB is not GRUB EFI but GRUB BIOS, which expects to chainload a boot
> > sector with AA55 signature instead of an EFI executable.
>
> is there any way around this?

First, check what GRUB flavour is running.
Type "c" at the GRUB menu to enter GRUB shell and type "set" to print 
environment variables. One contains the target architecture efi or pc.