Can GRUB boot GRUB?

[Iain Stephen]

Hi all,

I have two HDDs sda and hda.

sda (master SATA):
	WindowsXP (30GB)   Only because I need it for OU work.
	FC4       (200GB)  Because I love it.

hda (master IDE):
	Debian    (20GB)   Because I like trying other Linux's.

I would like to use hda for Debian (or perhaps testing FC5) but I want
GRUB on hda to be independent of GRUB on sda; so that if Debian updated
its version of GRUB's menu.lst I wouldn't need to edit menu.lst on sda.
What I'm looking for is a way for GRUB on sda to boot GRUB on hda in the
same way as GRUB can boot Windows.

I've tried googeling and reading the man pages and although there are
plenty of examples of editing menu.lst to boot other OS's I can't find
what I want, GRUB (sda) boot GRUB (hda).

Is it possible or have I just missed it?


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[Justin Willmert]

Iain Stephen wrote:
>  Hi all,
>
>  I have two HDDs sda and hda.
>
>  sda (master SATA):
>  	WindowsXP (30GB)   Only because I need it for OU work.
>  	FC4       (200GB)  Because I love it.
>
>  hda (master IDE):
>  	Debian    (20GB)   Because I like trying other Linux's.
>
>  I would like to use hda for Debian (or perhaps testing FC5) but I want
>  GRUB on hda to be independent of GRUB on sda; so that if Debian updated
>  its version of GRUB's menu.lst I wouldn't need to edit menu.lst on sda.
>  What I'm looking for is a way for GRUB on sda to boot GRUB on hda in the
>  same way as GRUB can boot Windows.
>
>  I've tried googeling and reading the man pages and although there are
>  plenty of examples of editing menu.lst to boot other OS's I can't find
>  what I want, GRUB (sda) boot GRUB (hda).
>
>  Is it possible or have I just missed it?
>     
You should be able to just chain load the Debian installation much like 
you would the Windows installation. Just give Debian the hda0 path 
rather than sdaX.

Take my comments as a grain of salt though. I am by NO means an advanced 
user in GRUB. I'm just telling you that I don't see much of a difference 
between the chain loading situations.

Justin Willmert

[Iain Stephen]

On Mon, 2006-02-20 at 12:18 -0600, Justin Willmert wrote:
>  You should be able to just chain load the Debian installation much
> like 
>  you would the Windows installation. Just give Debian the hda0 path 
>  rather than sdaX.
>  Take my comments as a grain of salt though. I am by NO means an advanced 
>  user in GRUB. I'm just telling you that I don't see much of a difference 
>  between the chain loading situations. 
That's what I thought too, but I can't get it to work. If I remember
correctly Debian starts booting but tries to use the FC4 filesystem on
sda and I get a kernel panic, or various GRUB errors depending on what
I've tried in menu.lst.

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[Billy Tallis]

On 2/20/06, Iain Stephen <i.stephen(a)tiscali.co.uk&gt; wrote:
>  On Mon, 2006-02-20 at 12:18 -0600, Justin Willmert wrote:
>  > You should be able to just chain load the Debian installation much like
>  > you would the Windows installation. Just give Debian the hda0 path
>  > rather than sdaX.
>  > Take my comments as a grain of salt though. I am by NO means an advanced
>  > user in GRUB. I'm just telling you that I don't see much of a difference
>  > between the chain loading situations.
>
>  That's what I thought too, but I can't get it to work. If I remember
>  correctly Debian starts booting but tries to use the FC4 filesystem on
>  sda and I get a kernel panic, or various GRUB errors depending on what
>  I've tried in menu.lst.
>  
If you truly have grub installed in the MBR of both drives and
pointing to different stage2 files, (ie if you installed one while the
other was not plugged in) than you can chainload one grub from the
other. If the bios loads grub on (hd0) then you would say "chainloader
(hd1)+1" and boot into the other grub. From there, you just need to
make sure that the kernel command line points to the right rootfs.

The chainloader is what you use for anything that would otherwise boot
itself, including DOS, Windows, and other bootloaders.

[jludwig]

On Monday 20 February 2006 14:37, Billy Tallis wrote:
>  On 2/20/06, Iain Stephen <i.stephen(a)tiscali.co.uk&gt; wrote:
>  > On Mon, 2006-02-20 at 12:18 -0600, Justin Willmert wrote:
>  > > You should be able to just chain load the Debian installation much like
>  > > you would the Windows installation. Just give Debian the hda0 path
>  > > rather than sdaX.
>  > > Take my comments as a grain of salt though. I am by NO means an
>  > > advanced user in GRUB. I'm just telling you that I don't see much of a
>  > > difference between the chain loading situations.
>  >
>  > That's what I thought too, but I can't get it to work. If I remember
>  > correctly Debian starts booting but tries to use the FC4 filesystem on
>  > sda and I get a kernel panic, or various GRUB errors depending on what
>  > I've tried in menu.lst.
>
>  If you truly have grub installed in the MBR of both drives and
>  pointing to different stage2 files, (ie if you installed one while the
>  other was not plugged in) than you can chainload one grub from the
>  other. If the bios loads grub on (hd0) then you would say "chainloader
>  (hd1)+1" and boot into the other grub. From there, you just need to
>  make sure that the kernel command line points to the right rootfs.
>
>  The chainloader is what you use for anything that would otherwise boot
>  itself, including DOS, Windows, and other bootloaders. 
At this point I have also
had problems with labeling of partitions.
Are the unique or unlabeled?
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Some people have opinions
I think I'll have a cheeseburger!

[Robert Nichols]

Iain Stephen wrote:
>  On Mon, 2006-02-20 at 12:18 -0600, Justin Willmert wrote:
>  
> >You should be able to just chain load the Debian installation much like 
> >you would the Windows installation. Just give Debian the hda0 path 
> >rather than sdaX.
> >Take my comments as a grain of salt though. I am by NO means an advanced 
> >user in GRUB. I'm just telling you that I don't see much of a difference 
> >between the chain loading situations.
>  
>  
>  That's what I thought too, but I can't get it to work. If I remember
>  correctly Debian starts booting but tries to use the FC4 filesystem on
>  sda and I get a kernel panic, or various GRUB errors depending on what
>  I've tried in menu.lst. 
I've done that with FC3 and FC4 and had no problem at all.
Just be sure that Debian's grub.conf and /etc/fstab reference
the right partitions.  In grub.conf check both the "root ..."
line and the "root=..." kernel parameter.  If you're using
"LABEL=..." to identify partitions, make sure all your
partitions have unique labels.

-- 
Bob Nichols         Yes, "NOSPAM" is really part of my email address.

[Iain Stephen]

On Mon, 2006-02-20 at 12:18 -0600, Justin Willmert wrote:
>  You should be able to just chain load the Debian installation much
> like 
>  you would the Windows installation. Just give Debian the hda0 path 
>  rather than sdaX.
>  Take my comments as a grain of salt though. I am by NO means an advanced 
>  user in GRUB. I'm just telling you that I don't see much of a difference 
>  between the chain loading situations. 
That's what I thought too, but I can't get it to work. If I remember
correctly Debian starts booting but tries to use the FC4 filesystem on
sda and I get a kernel panic, or various GRUB errors depending on what
I've tried in menu.lst.

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/ \ Regards, Iain.

[Mike McCarty]

Iain Stephen wrote:
>  Hi all,
>  
>  I have two HDDs sda and hda.
>  
>  sda (master SATA):
>  	WindowsXP (30GB)   Only because I need it for OU work.
>  	FC4       (200GB)  Because I love it.
>  
>  hda (master IDE):
>  	Debian    (20GB)   Because I like trying other Linux's.
>  
>  I would like to use hda for Debian (or perhaps testing FC5) but I want
>  GRUB on hda to be independent of GRUB on sda; so that if Debian updated
>  its version of GRUB's menu.lst I wouldn't need to edit menu.lst on sda.
>  What I'm looking for is a way for GRUB on sda to boot GRUB on hda in the
>  same way as GRUB can boot Windows. 
Ok. I'm not sure why you want to do it this way, but GRUB should have
no problem chain loading either from the MBR of hda, or from the BR
of one of the partitions on hda.

I suggest that you try making a GRUB boot floppy, and getting it
to work from there. Try to create a version of GRUB that can
chain load any of WinXP, FC4, and Debian GRUB. It should just
take a simple chainload. That way you can disentangle your work
from possibly breaking your current boot capabilities.

If you don't have a floppy, then GET one! Playing around with boot
when you don't have a flopy is not the way to go, IMO.

Mike
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[James Wilkinson]

Iain Stephen wrote:
>  I would like to use hda for Debian (or perhaps testing FC5) but I
> want
>  GRUB on hda to be independent of GRUB on sda; so that if Debian updated
>  its version of GRUB's menu.lst I wouldn't need to edit menu.lst on sda.
>  What I'm looking for is a way for GRUB on sda to boot GRUB on hda in the
>  same way as GRUB can boot Windows. 
What works for me:

title Fedora Core 5 test
        rootnoverify (hd1,5)
        chainloader +1

The FC5 test has grub installed on the boot sector of /dev/hdb6.

I'd imagine that if you have grub installed on the MBR of hda, you'd
want
        rootnoverify (hd1)
assuming that your BIOS is set to boot from SATA by preference.

Hope this helps,

James.

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Can GRUB boot GRUB? [solved]

[Iain Stephen]

Hi all,

Thanks for all your suggestions, finally got it working. Needed the
'map' line for it to work.

title Debian
	map (hd1) (hd0)
	rootnoverify (hd1,0)
	chainloader (hd1)+1

Once again thanks for your help.

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