Re: Force location of GRUB's boot and core images ?

[Pascal Hambourg]

Le 09/04/2017 à 16:35, Xen a écrit :
> Pascal Hambourg schreef op 09-04-2017 13:52:
> > Le 09/04/2017 à 12:09, Xen a écrit :
> > > Pascal Hambourg schreef op 09-04-2017 10:14:
> > > > In some cases I would need to force installation of GRUB's boot and
> > > > core images into a specific location on the drive instead of letting
> > > > grub-install decide automatically.
> > > >
> > > > For example :
> > > > - install the boot image in the first sector of an unformatted
> > > > partition
> > > > - install the core image in the second and next sectors of that
> > > > partition.
> > >
> > > Do you mean that the partition being unformatted makes a difference?
> >
> > Yes. IME, grub-install refuses embedding on a partition with an
> > unknown format, e.g. an empty partition. And I need embedding.
>
> Can you tell me what your use case is, out of interest?

My current use case is to install a new GNU/Linux system entirely in an 
encrypted (LUKS) partition on a disk which already contains an existing 
GNU/Linux system. The existing boot loader is installed in the MBR and 
must be left untouched. However it cannot boot the new system because 
even /boot is encrypted. So I need to install GRUB with encryption 
support as a secondary boot loader. Its boot and core images cannot be 
installed in the encrypted partition.

A more general use case is to install multiple instances of GRUB as 
independent secondary boot loaders, and not store the core image as a 
standard file using blocklists because it is not reliable.

> Of course perhaps your partition is very small and you have no intended
> use for the partition.

The only intended use for the partition is to install GRUB, and I want 
it as small as possible. Boot image + core image take less than 100 kB 
and I'd rather avoid allocating a multi-GB btrfs partition for this.