[SOLVED] Make GRUB find ubuntu?

Reded · 2012-02-25 17:23:44

Hey all, I think I need a bit of a shove in the right direction for this.

Essentially I used Ubuntu for a while, and decided to try Arch. So I partitioned my drive using GParted on a Ubuntu LiveCD. I have sda1 (Ubuntu) And sda3 (Arch). Both these partitions show up on GParted.

However, when I switch my computer on, the only two options in GRUB are Arch, and Arch fallback.

I'm assuming there's something I missed during installation or something, but GRUB doesn't seem to find the Ubuntu partition.

The Wiki says to add this to the menu.lst:

title Other Linux
root (hd0,2)
kernel /path/to/kernel root=/dev/sda3 ro
initrd /path/to/initrd

That's all well and good, but I don't know what to fill in the blanks with, namely the /path/to/kernel part, and the /path/to/initrd.

There's also another section, concerning GRUB2 (It says Ubuntu 9.10+, my ubuntu is 11.10, so I guessed this was right), where it says to add this:

# other Linux using GRUB2
title Ubuntu
root (hd0,2)
kernel /boot/grub/core.img

Again, I'm not sure if there's any blanks I need to fill in there (I did actually just copy that in directly, but it said unable to find /boot/grub/core.img), so any help would be appreciated - I could do with at least getting on the Ubuntu install every now and then, though I'm slowly phasing it out in favour of Arch.

Last edited by Reded (2012-02-25 18:45:24)

KingX · 2012-02-25 18:08:43

All you need to do is boot into arch and edit your menu.lst and add an entry for Ubuntu. If you are sure Ubuntu is on /dev/sda1 then after booting into arch mount /dev/sda1 onto mount using this command

 sudo mount /dev/sda1 /mnt/

Then do

 ls /mnt/boot/

and post the output here. That will tell us the name of the kernel and initrd image.

Lennie · 2012-02-25 18:11:16

Ubuntu has symlinks to the newest installed kernel directly under / , so the easiest is:

title Ubuntu
root (hd0,0)
kernel /vmlinuz root=/dev/sda1 ro
initrd /initrd.img

The second alternative (kernel /boot/grub/core.img) is for chainloading, then you need to install grub on Ubuntu's partiton.

Reded · 2012-02-25 18:13:22

Nice big string of output here from ls /mnt/boot/

abi-3.0.0-12-generic memtest86+.bin
abi-3.0.0-15-generic memtest86+_multiboot.bin
abi-3.0.0-16-generic System.map-3.0.0-12-generic
config-3.0.0-12-generic System.map-3.0.0-15-generic
config-3.0.0-15-generic System.map-3.0.0-16-generic
config-3.0.0-16-generic vmcoreinfo-3.0.0-12-generic
extlinux vmcoreinfo-3.0.0-15-generic
grub vmcoreinfo-3.0.0-16-generic
initrd.img-3.0.0-12-generic vmlinuz-3.0.0-12-generic
initrd.img-3.0.0-15-generic vmlinuz-3.0.0-15-generic
initrd.img-3.0.0-16-generic vmlinuz-3.0.0-16-generic

Will I need to put the whole initrd.img-3.0.0-16-generic or will just initrd.img do?

Last edited by Reded (2012-02-25 18:19:19)

Reded · 2012-02-25 18:40:16

OK, so this is what I put in /boot/grub/menu.lst -

title Ubuntu
root (hd0,0)
kernel /vmlinuz-3.0.0-16-generic root=/dev/sda1 ro
initrd /initrd.img-3.0.0-16-generic

After trying to use it, it said /vmlinuz-3.0.0-16-generic was not found.

Thorsten Reinbold · 2012-02-25 18:41:32

You could also install os-prober.

Reded · 2012-02-25 18:45:07

All fixed, changed the part to -

title Ubuntu
root (hd0,0)
kernel /boot/vmlinuz-3.0.0-16-generic root=/dev/sda1 ro
initrd /boot/initrd.img-3.0.0-16-generic

Forgetting the /boot part, dumb mistake!

Solved, thanks everyone for helping.

Jristz · 2012-02-25 22:36:06

and os-prober work

almost for me work when I use a dualbot

Arch Linux

#1 2012-02-25 17:23:44

[SOLVED] Make GRUB find ubuntu?

#2 2012-02-25 18:08:43

Re: [SOLVED] Make GRUB find ubuntu?

#3 2012-02-25 18:11:16

Re: [SOLVED] Make GRUB find ubuntu?

#4 2012-02-25 18:13:22

Re: [SOLVED] Make GRUB find ubuntu?

#5 2012-02-25 18:40:16

Re: [SOLVED] Make GRUB find ubuntu?

#6 2012-02-25 18:41:32

Re: [SOLVED] Make GRUB find ubuntu?

#7 2012-02-25 18:45:07

Re: [SOLVED] Make GRUB find ubuntu?

#8 2012-02-25 22:36:06

Re: [SOLVED] Make GRUB find ubuntu?

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