[multi-booting] editing grub post-install

elephantos · 2008-03-03 05:00:41

Hey everyone, i'm installing Arch as a tertiary OS on one drive (w/ XP and Ubuntu). In the installation i skipped writing the bootloader to the MBR as I don't want to lose boot data on the existing grub menu. I know I could manually edit them in later, but I think that may be too risky atm.

the arch installation is on partition on /dev/sda4, while ubuntu is sda3. In menu.lst, ubuntu is (hd0,2) and xp is (hd0,0). guesswork has led me to making arch (hd0,3) as I think they are supposed to go in left-right order on the disk.

So, I was thinking I can manually edit menu.lst to add an option for booting Arch:

title  Arch Linux
root  (hd0,3)
kernel  /boot/vmlinuz26 root=/dev/sda4 ro
initrd  /boot/kernel26.img

I tried removing /boot/ in the kernel and initrd paths, same error after selecting Arch Linux in grub on startup:

Error 15: File not found

Is my logic correct, am I missing something obvious, or something else?

rossm · 2008-03-03 06:16:28

Hi there,
Could it be that as you are using ubuntu's grub your partition should be called "hda3 in" ubuntu /boot/grub/menu.lst.

bslagowski · 2008-03-03 06:28:46

What was the error you got on boot? I don't think you'd need to remove the "/boot/..." part. Post your fstab and be sure to mark out which partitions are for which distros.

veek · 2008-03-03 09:32:31

Hmm seems grub can't find your kernel.

First, are you sure you installed the kernel during setup? If you skipped installing
grub maybe you forgot to install the kernel. I think I've done something like that before.
I would look in your boot folder and make sure the files are there, that will eliminate one possibility.

And yea posting the fstab will help, I guess the easiest way is to access it from Ubuntu.

Post the output of fdisk -l, too.

Additionally, do you have a separate boot partition containing the kernel and initrd?
The root line in menu.lst needs to point to the partition containing the kernel.

KimTjik · 2008-03-03 10:42:31

A part of my Arch entry looks like this:

kernel /vmlinuz26 root=/dev/sda13 ro vga=773
initrd /kernel26.img

I boot directly from another grub bootloader with these parameters. Notice there aren't any "/boot" part. Why not try without that part, just as in my example above.

I've noticed that some changes have been done in other distros as well. In some you still see the "/boot/vmlinuz*" but in many it's gone. It's just a guess since I'm not very good at this.

bgc1954 · 2008-03-03 16:13:36

Check your boot partition and your root / filesystem. You will find whether there is a symlink to the boot partion in the root fielsystem or not. I'm quite sure that Arch doesn't put a symlink to the root filesystem like Ubuntu and Debian do so you probably need the /boot/vmlinuz26 part.

bslagowski · 2008-03-03 16:29:42

I know my Arch installation lacks the the symlinks, which is why I suggested not removing the /boot. I realize other distros may do so. It'd still be nice to see your fstab.

KimTjik · 2008-03-03 19:51:04

I see that I read some posts here badly, hence my post became a bit off target. Nevertheless this makes me wonder why it works with or without these symlinks (unfortunately not yet for our friend elephantos). I don't have any symlinks and still it boots just fine without "/boot" direction.

Can you explain that for me?

bgc1954 · 2008-03-03 20:55:43

Here is my /boot/grub/menu.lst and as you can see some are /boot/etc. and some are not:

#  Config file for GRUB - The GNU GRand Unified Bootloader
# /boot/grub/menu.lst

# DEVICE NAME CONVERSIONS 
#
#  Old /dev    DevFS                    Grub
# -----------------------------------------------
#  /dev/fd0    /dev/floppy/0            (fd0)
#  /dev/hda    /dev/discs/disc0/disc    (hd0)
#  /dev/hdb2   /dev/discs/disc1/part2   (hd1,1)
#  /dev/hda3   /dev/discs/disc0/part3   (hd0,2)
#

#  FRAMEBUFFER RESOLUTION SETTINGS
#     +----------------------------------------+
#          | 640x480 800x600 1024x768 1280x1024
#      ----+-----------------------------------
#      256 |   0x301   0x303    0x305     0x307
#      32K |   0x310   0x313    0x316     0x319
#      64K |   0x311   0x314    0x317     0x31A
#      16M |   0x312   0x315    0x318     0x31B
#     +----------------------------------------+

# general configuration:
timeout   10
default   0
color light-cyan/black white/blue

# boot sections follow
# each is implicitly numbered from 0 in the order of appearance below
#
# TIP: If you want a 1024x768 framebuffer, add "vga=773" to your kernel line.
#
# TIP: To use udev, add "devfs=nomount" to your kernel line.
#
#-*

title  Arch Linux 64 bit (Default Linux Desktop)
root   (hd0,4)
kernel /boot/vmlinuz26 root=/dev/sda5 ro vga=791
initrd /boot/kernel26.img

title  Windows XP Professional
root   (hd0,0)
makeactive
chainloader +1

title  Debian 64 bit Linux (Etch)
root  (hd0,6)
kernel /vmlinuz root=/dev/hda7 ro vga=791
initrd /initrd.img

title Ubuntu 64 bit Linux (Hardy Heron)
root   (hd0,7)
kernel /vmlinuz root=/dev/sda8 ro vga=791 quiet splash
initrd /initrd.img

title  Fedora 64 bit Linux (8.0)
root   (hd0,8)
kernel /boot/vmlinuz root=/dev/sda9 ro vga=791 rhgb quiet
initrd /boot/initrd.img

title  Mandriva 64 bit Linux (2008.0)
root  (hd0,11)
kernel /boot/vmlinuz-desktop root=/dev/hda12 ro vga=791 splash=silent
initrd /boot/initrd-desktop.img

title  Mepis 64 bit Linux (7.0)
root  (hd0,10)
kernel /boot/vmlinuz root=/dev/sda11 ro vga=791 splash
initrd /boot/initrd.img

title Suse 64 bit Linux (11.0)
root  (hd0,14)
kernel /boot/vmlinuz root=/dev/sda15 vga=0x317 resume=/dev/sda3 splash=silent showopts
initrd /boot/initrd

title Sidux 64 bit Linux
root  (hd0,12)
kernel /boot/vmlinuz-2.6.21.3-slh64-smp-4 root=/dev/hda13 ro vga=788 quiet splash
initrd /boot/initrd.img-2.6.21.3-slh64-smp-4

title  Dreamlinux 32 bit Linux (3.0-beta)
root   (hd0,9)
kernel /boot/vmlinuz-2.6.23.12-dream root=/dev/hda10 ro vga=791 quiet splash=silent
initrd /boot/initrd.img-2.6.23.12-drem

#title Vector 64 bit Linux (5.9 Beta)
#root  (hd0,9)
#kernel /vmlinuz root=/dev/hda10 ro vga=791

#title Slackware 32 bit Linux (12.0)
#root (hd0,)
#kernel /boot/vmlinuz root=/dev/hda ro vga=791

title PCLinux OS 32 bit (2007)
root (hd0,13)
kernel /boot/vmlinuz root=/dev/hda14 ro vga=791
initrd /boot/initrd.img

#title Mint 32 bit Linux (4.0 fluxbox beta-028)
#root  (hd0,)
#kernel /vmlinuz root=/dev/hda ro quiet splash
#initrd /initrd.img

#title gOS 32 bit Linux (1.01)
#root  (hd0,)
#kernel /vmlinuz root=/dev/hda ro vga=791 quiet splash
#initrd /initrd.img

#title Elive 32 bit Linux (beta)
#root (hd0,12)
#kernel /vmlinuz root=/dev/hda13 ro vga=788 quiet splash
#initrd /initrd.img

#title Geubuntu 32 bit linux (7.10)
#root (hd0,14)
#kernel /vmlinuz root=/dev/hda15 ro quiet splash
#initrd /initrd.img

I play around with quite a few flavours of linux from time to time just to see if there are things I might like done differently on my Arch linux.

Misfit138 · 2008-03-03 21:47:12

KimTjik wrote:

I see that I read some posts here badly, hence my post became a bit off target. Nevertheless this makes me wonder why it works with or without these symlinks (unfortunately not yet for our friend elephantos). I don't have any symlinks and still it boots just fine without "/boot" direction.
Can you explain that for me?

See the section 'GRUB' in the Beginner's Guide in the wiki. I just expanded it recently to include such an explanation.

KimTjik · 2008-03-03 22:05:00

Thanks Misfit128! Sometimes the most obvious doesn't strike me. Anyway better late than never.

veek · 2008-03-04 01:01:50

There's a logical explanation for whether you need /boot in your kernel path or not. It has to do with
where your kernel is, and whether it's on your root partition or a separate boot partition. It can be confusing
because there are several scenarios that appear similar, but are actually different.

In one case /boot is actually a folder on your root partition containing the kernel. In the other case /boot
is a mount point for the separate partition containing the kernel (assuming you specify a mount
point for the partition during arch install). If /boot is a folder on your root partition, then you need /boot in the
kernel path. If it's a mount point for a separate partition, chances are you don't need /boot in the kernel path,
because the kernel is at the top level of that separate partition.

The command 'root (hdx, n)' is simply pointing at the top level of whatever partition contains your kernel.
So if the kernel is in a folder on your root partition, the full path is: (hdx, y)/boot/vmlinuz26. If it's at the
top level of a separate partition, then the full path is: (hdx, z)/vmlinuz26. A third possibility is that it's in a folder
on a separate partition so the full path is: (hdx, z)/foldername/vmlinuz26.

It's a little bit difficult to explain concisely, hopefully that made sense. I might make another thread giving detailed
examples that show what the paths in grub look like for different scenarios.

Arch Linux

#1 2008-03-03 05:00:41

[multi-booting] editing grub post-install

#2 2008-03-03 06:16:28

Re: [multi-booting] editing grub post-install

#3 2008-03-03 06:28:46

Re: [multi-booting] editing grub post-install

#4 2008-03-03 09:32:31

Re: [multi-booting] editing grub post-install

#5 2008-03-03 10:42:31

Re: [multi-booting] editing grub post-install

#6 2008-03-03 16:13:36

Re: [multi-booting] editing grub post-install

#7 2008-03-03 16:29:42

Re: [multi-booting] editing grub post-install

#8 2008-03-03 19:51:04

Re: [multi-booting] editing grub post-install

#9 2008-03-03 20:55:43

Re: [multi-booting] editing grub post-install

#10 2008-03-03 21:47:12

Re: [multi-booting] editing grub post-install

#11 2008-03-03 22:05:00

Re: [multi-booting] editing grub post-install

#12 2008-03-04 01:01:50

Re: [multi-booting] editing grub post-install

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