Good thoughts Nick. In fact after you left we went for "Thought 3" and
now he can get into all OS's with LILO.
For all of yesterday's installees (is that a real word?), here are some
notes I have which might be helpful:-
(Obviously change hdax to whatever your system uses)
To fix things using the Gentoo Boot CD:
* Boot from the CD
* swapon /dev/hdb2
* mount /dev/hdb3 /mnt/gentoo
* mount /dev/hdb1 /mnt/gentoo/boot
* mount -t proc proc /mnt/gentoo/proc
* chroot /mnt/gentoo /bin/bash
* env-update
* source /etc/profile
....then fix whatever and reboot
On Sun, 2004-05-16 at 11:35, Nick Rout wrote:
> At the conclusion of Howard's gentoo install yesterday, Howard had a
> problem with grub.
>
> To recap, Howard had the following OSes in this order on his HD: XP,
> Mandrake, Gentoo. Before we proceeded with gentoo he was booting with
> LILO from Mandrake. Once we set up grub in gentoo a blank screen
> appeared instead of the grub menu, no grub prompt, just a blank screen.
>
> I am pleased to see that after I left someone managed to get back into
> his mandrake system and run lilo to get him back to square one :-).
> However it would be nice to give him access to his gentoo system.
>
> The gentoo system is in something like hda8 (root) & hda9 (boot)
> although I am not sure of the exact numbers so I will use hdagroot and
> hdagboot to avoid confusion.
>
> THOUGHT 1
> =========
> Is grub actually installed where we think it is? From inside the
> chrooted gentoo environment run the find command from inside grub viz:
>
> #grub [run the grub prompt]
> grub> find /boot/grub/stage2 [look for grub on every partition]
> (hd0,2) [on my system its on (hd0,2) or /dev/hda3]
>
> make sure that the partition where grub is installed is the partition
> specified when you set up grub, viz (on my system):
> grub> root (hd0.2) <--- must match the result of find
> grub> setup (hd0)
> grub> quit
>
> THOUGHT 2
> =========
> grub installs a 512 byte stage_1 program in the MBR, ie at the very
> start of the drive. 512b is too small to know about the operation of
> file systems, so it hard codes in the block addresses of the stage_1.5
> file that knows how to work the filesystem where the stage_2 program is
> stored, stage_2 does the real work. I suspect that grub stage_1 may not
> be able to reach the stage_1.5 file which is stored a long way into
> Howard's hard drive. I see that the grub setup program has a --force-lba
> option and it may be worth trying this, so the sequence to install grub
> would be (once inside the gentoo chroot environment)
>
> #grub
> grub> root (hd0,x)
> [where x is the partition number of the gentoo boot partition,]
> [remembering that hda7 is (hd0,6) etc]
> grub> setup --force-lba (hd0)
> grub> quit
>
> THOUGHT 3 (probably the easiest, apart from my desire to actually
> troubleshoot Howards's grubby problem)
> ==================================================================
> Include gentoo under mandrake's lilo system.
> lilo needs access to the kernel you want to boot when it embeds itself
> in your MBR, in other words when you run lilo after a configuration
> change.
>
> 1. Boot into mandrake
> 2. mount the gentoo boot partition
>
> # mkdir /mnt/genboot
> # mount /dev/hdagboot /mnt/genboot
>
> 3. check the kernel and initrd names
>
> # ls /mnt/genboot/
>
> should return, among the other contents, something like:
> kernel-2.5.6-gentoo-r1 initrd-2.5.6-gentoo-r1
>
> 4. add the following to /etc/lilo.conf (ie in the mandrake filesystem)
>
> image=/mnt/genboot/boot/kernel-2.5.6-gentoo-r1
> label=Gentoo
> read-only
> root=/dev/ram0
> append="init=/linuxrc real_root=/dev/hdagroot"
> initrd=/mnt/genboot/boot/initrd-2.6.5-gentoo-r1
>
>
> (actually those instructions are for a system with an initrd, if Howard
> didn't do an initrd it will be like this:
>
> image=/mnt/genboot/boot/kernel-2.5.6-gentoo-r1
> label=Gentoo # Name we give to this section
> read-only # Start with a read-only root. Do not alter!
> root=/dev/hdagroot # Location of the root filesystem
>
> 5. run lilo to take in the changes you just made. run it with the -v
> option so you can see that it is doing its thing
>
> # lilo -v
>
> will spew out some messages about finding (or not finding) various
> things.
Robert Fisher
www.fisher.net.nz
BOFH Excuse #306:
CPU-angle has to be adjusted because of vibrations coming from the
nearby road
