Re: Grub, UEFI Secure Boot and netboot - help!

On Mon, Jun 10, 2019 at 04:35:33PM +0100, Colin Watson wrote:
>On Mon, Jun 10, 2019 at 04:15:22PM +0100, Steve McIntyre wrote:
>> 
>> The prefix variable is very much a single value, yes. It's used and
>> dereferenced all over the place inside grub as a single const char
>> *. Not something I'm about to play with!
>
>It'd be totally possible to make the grubnet memdisk try multiple
>prefixes: there's already a memdisk that looks in a couple of locations
>under $prefix for grub.cfg, so it could separate it into a list and try
>each one until it finds something usable.
>
>However, that approach embeds the debian-installer path even in images
>that have nothing to do with d-i; so I think on balance I prefer the
>idea of adding another d-i-specific image.  Steve is working on that
>now.

Yup. Simple changes. \o/

>> >It's been a long time since I've played with any of this but I have a
>> >vague recollection of once upon a time using (or trying to use, maybe
>> >I'm remembering a failed experiment) a memdisk (builtin to the grub
>> >image) containing an initial config file which then was a bit more
>> >flexible about chaining to the next thing. I can't find any evidence
>> >of that setup in any of the places I thought it might be related to
>> >though :-/
>> 
>> Right. That's how various other things work - it's how we control
>> things for CD boot, for example. But network boot is a slightly
>> different configuration. It's simply a single binary rather than a FAT
>> image containing the binary and config.
>
>Moot given the above, but this isn't actually true - search for
>grub-netboot.cfg and memdisk-netboot.fat in build-efi-images.

I sit corrected. :-)