Multiboot with Grub
Post # 121 permalink Topic #121 by mreschke on 2008-12-22 15:22:04 (viewed 506 times)

Ultimate Multiboot[-][- -][++]

  1. Always leave the 3 primary partitions as large ones, to use for OS's that must be installed on primary
  2. Remeber, max 15 partitions (or is it 14, sda14?)
  3. If you have multiple drives, use only 1 swap to save partition numbers
  4. Pick 1 super small fast distro as your main distro which uses /boot. (or not? just grib-install to boot part?)
  5. Very Important (see Differences in partition formatting below) Format all drives and partition with the same OS, newer e2fs formatters are incompatible, grub won't be able to read a newer ext3 and your screwed. So dont let the installer format them, format them yourself with a constant os and e2fsprogs formatter.

Differences in partition formating[-][- -][++]

I ran into a few problems with ext3 formatting versions. My main grub is from fedora 9, so version whatever. When I installed foresight linux, I used the installer to re-format the destination as ext3 and now my older main grub won't chainload to it, does not know its ext3 because it was formated with a newer formatter. The solution is to format all partitions with the same formatter, then during installs, DON'T format the drive again, just leave it as unchanged. After formatting sdb10 with my old ubuntu, and installing foresight linux on it, without re-formatting, it worked great, chainloads perfectly.

Other[-][- -][++]

Installed gOS to second HD, did grub go (hd1,4) so /dev/sdb5
Now if we didn't chainload, and wanted to call the kernel directly I had to do

Code Snippet
title         gOS
rootnoverify  (hd1,4)
kernel        (hd1,4)/boot/vmlinuz-2.6.24-19-generic root=/dev/sdb5
initrd        /boot/initrd.img-2.6.24-19-generic

You just have to play with the root (try hdb5 and sdb5), and put (hd1,4) before /boot/vml.. and maybe before /boot/initrd too

Fix grub after reload windows[-][- -][++]

https://help.ubuntu.com/community/RecoveringUbuntuAfterInstallingWindows
see the 'Overwriting the Windows bootloader' part

The easiest way to setup a multiboot is to install windows first (since it does not allow alternate boot changes), then install linux and let grub do all the work.

If you have to re-load windows it will erase your MBR and only windows will boot.

To get your old grub back, do this AFTER windows is done installing and boots well.

Boot from a linux CD or USB drive
Goto a terminal
In this example, my HD is sda and sda12 is my Fedora 9 install which is the only OS that actually uses the separate partition of /boot (sda7) instead of it's own folder /boot. So Fedora 9 is sda12 and the actual boot partition is sda7.

Install grub files to a drive (will not set default grub partition)[-][- -][++]

Code Snippet
# mkdir /mnt/root
# mount -t ext3 /dev/sda12 /mnt/root
# mount -t ext3 /dev/sda7 /mnt/root/boot
# grub-install --root-directory=/mnt/root /dev/sda

Reboot and all is original (grub) again. Nice!

Addition, install Zenwalk on my multi-boot laptop, it removed loader from MBR, so nothig boots, the above steps did not work for me (laptop hda7 points to /boot on hda5).
Gives error
Could not find device in BIOS (or something like that)
did a grub-install --recheck /dev/hda which gave this error
Could not find device for /boot
Found this http://ubuntuforums.org/showthread.php?t=504678 which said to fix grud do:

Set default grub device[-][- -][++]

Code Snippet
$ sudo grub
> find /boot/grub/stage1
which returns (hdX,Y)
> root (hdX,Y)
> setup (hdX)

this actuall works best, and all the time, forget the find part too, just add your /boot partition, remember grub starts on 0, so if you /boot is hda5 then do root (hd0,4) and setup (hd0), done!!

Just Re-install it[-][- -][++]

If you cannot get a linux OS to load, try re-installing grub on it. Example, after installing linux mint to my second /dev/sdb7 HD, I could not chainload to it from my /dev/sda main grub. I couldn't even do a direct kernel and initrd load, even though I told the installer to install grub to itself /dev/sdb7, strange. I simply booted my normal /dev/sdb ubuntu install, mounted /dev/sdb7 to /tmp/dd/ then re-installed grub to it with grub-install --root-directory=/tmp/dd/ /dev/sdb7 then my normal chainload to sdb worked great. So perhaps it's didn't get installed correctly? I found that foresight linux did the same thing, so I just re-installed grub to that and it chainloaded fine.

Example, 100+ systems menu.lst[-][- -][++]

Grub2 Framebuffer[-][- -][++]

GRUB_GFXMODE, framebuffer, grub2, hwinfo, vga, uvesafb

dont use the Arch way of payload=keep, use uvesafb
http://idyllictux.wordpress.com/2010/04/26/lucidubuntu-10-04-high-resolution-plymouth-virtual-terminal-for-atinvidia-cards-with-proprietaryrestricted-driver/

This is nice, but dont use. Use the link above for framebuffer stuff
http://wiki.archlinux.org/index.php/GRUB2

Resources[-][- -][++]

  1. http://www.justlinux.com/forum/showthread.php?t=144294
  2. http://www.justlinux.com/forum/showthread.php?threadid=143973

Keywords

boot multiboot linux grub menu.lst list partition hard drive harddrive