[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Calling Grub in MBR on a USB disk from Grub on a primary disk probl
From: |
Marcin Zajączkowski |
Subject: |
Re: Calling Grub in MBR on a USB disk from Grub on a primary disk problem |
Date: |
Sun, 26 Jul 2009 23:56:14 +0200 |
On Sun, 26 Jul 2009 23:51:11 +0200
Marcin Zajączkowski <address@hidden> wrote:
> Thanks Muchael for your answer!
Michael of course :).
> I didn't have access to that machine during a week and I couldn't
> answer earlier.
>
>
> On 2009-08-20 15:14:37 -0700 Michael Evans wrote:
>
> > What I've found is that modern PC BIOSes are increasingly trying to
> > be too smart and thus acting even more stupid than they should be.
> > It seems that they assume an old 1980s based operating system will
> > be used and remap the devices such that whichever one is actually
> > booting is the 0th and primary bios device. Your USB device -may-
> > look like a floppy to the BIOS.
> >
> > My suggestion is to install grub as a whole-disk setup on whatever
> > device you want to boot from, and include a file on that device that
> > you can search for. Boot off that device, find the file, and modify
> > your device map accordingly.
>
> I checked it, but it seems that my USB disk is always mapped as hd1
> when booted from primary HDD and as hd0 and booted from USB drive,
> but with your suggestion I was able to locate boot partition and with
> following modifications I'm able to boot!
>
> title Fedora direct
> root (hd1,4)
> kernel /vmlinuz-(...)
> initrd /initrd-(...)
>
> > Unfortunately you should not assume any other devices will remain
> > constant, or even predictable.
>
> Mentioned solution works (and I'm very happy with that!), but it
> requires to modify grub.conf with every new installed kernel version.
>
> Maybe you have some further ideas how could I debug my system from
> GRUB point of view to make GRUB from the secondary disk MBR bootable?
>
>
> Regards
> Marcin