Re: Is it possible to have grub2's boot.img as my MBR, but have it look in a separate partition for core.img?

[edgar . soldin]

I had also problems to install grub2 to a partition boot record. It 
complained and wouldn't do it. But it was necessary, because the laptop 
bios I wanted to boot the usb stick, did actually ignore the mbr but 
insisted on starting the partition boot record.

I compiled a g2ldr and used the latest grubinst-1.1-bin-w32-2008-01-01 
to install grub into mbr and the partitions boot record using the grub2 
flag. This worked only when g2ldr was present on the root of the 
partitions fat32 fs.

Can anybody explain the difference of this approach and why it works?

thanks ede



On 28.01.2010 12:45, Colin Watson wrote:
> On Thu, Jan 28, 2010 at 03:37:44AM +0000, Wesley Smith wrote:
> > I am sorry to bother you, but reading the docs has not helped, and Googling has
> > turned up only other people suffering from the same problem, but not the
> > solution to it.
> >
> > I have a multiboot system that I would like to use Grub to manage. The version
> > of Grub shipping with my Linux distro is Grub2, and it installs its equivalent
> > of core.img into the remaining sectors on the first track after the MBR but
> > before the first partition. Unfortunately, those sectors are needed by another
> > program.
> >
> > I have a separate primary /boot partition, with the rest of my Linux distro
> > stored in an LVM. If I could only keep boot.img as my MBR but have it look in
> > the /boot partition for core.img rather than having it read an embedded one from
> > the sectors immediately following the MBR, everything would work fine. Is this
> > possible with Grub2?
>
> Yes, you can do this by using 'grub-install /dev/sda1' (or whatever the
> device name for your /boot partition is).
>
> Note that this setup typically requires the use of blocklists, which are
> inherently unreliable.  For example, you may find that you need to
> re-run grub-install after certain filesystem operations; see the "And
> blocklists?" section of http://grub.enbug.org/BIOS_Boot_Partition for a
> description of the problem.  This problem was present in GRUB Legacy as
> well, although it did not warn about it.