How To Dual Boot FreeBSD and Windows XP using GRUB

Ever needed to dual boot Windows XP with FreeBSD and wanted to do it via Grub?

Well, here’s how!

This document assumes that Windows XP is installed on the first partition (i.e. /dev/ad0s1 in freebsd parlance) and that FreeBSD is on the second partition (i.e. /dev/ad1s1), thats the setup on my laptop anyway :)

First install the port:-

cd /usr/ports/sysutils/grub
make install

Now create the “menu.lst” file:-

vi /boot/grub/menu.lst

# For booting FreeBSD

title FreeBSD
root (hd0,1,a)
kernel /boot/loader

# For booting Windows XP

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

NOTE: This will make FreeBSD the default OS

Make MBR writable:-

sysctl kern.geom.debugflags=16

NOTE: if you do not use the above command then you will not be able to run the grub-install script, it will dump out with something like this:-

[zaphod] /boot/grub# grub-install hd0

GNU GRUB version 0.97 (640K lower / 3072K upper memory)

[ Minimal BASH-like line editing is supported. For the first word, TAB
lists possible command completions. Anywhere else TAB lists the possible completions of a device/filename. ]
grub>; root (hd0,1,a)
Filesystem type is ufs2, partition type 0xa5
grub>; setup --stage2=/boot/grub/stage2 --prefix=/boot/grub (hd0)
Checking if "/boot/grub/stage1" exists... yes
Checking if "/boot/grub/stage2" exists... yes
Checking if "/boot/grub/ufs2_stage1_5" exists... yes
Running "embed /boot/grub/ufs2_stage1_5 (hd0)"... failed (this is not fatal)
Running "embed /boot/grub/ufs2_stage1_5 (hd0,1,a)"... failed (this is not fatal)
Running "install --stage2=/boot/grub/stage2 /boot/grub/stage1 (hd0) /boot/grub/stage2 p /boot/grub/menu.lst "... failed

Error 29: Disk write error
grub>; quit

grub-install script

The grub-install script saves you from having to install the various components manually using the grub command line interface.

grub-install hd0

NOTE: hd0 is listed in the /boot/grub/device.map file to map to the correct device (i.e. /dev/ad0)

More info is available here:-

http://www.gnu.org/software/grub/

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This entry was posted on Friday, May 23rd, 2008 at 5:09 pm and is filed under dual booting, freebsd, grub, windows xp. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

6 Responses to “How To Dual Boot FreeBSD and Windows XP using GRUB”

  1. Wirasto S. Karim says on April 29th, 2009 at 8:07 pm :

    Nice article :)
    Thank’s

  2. Sai Vinoba says on May 8th, 2009 at 8:29 am :

    Hi Ubergeek,
    >>
    … that FreeBSD is on the second partition (i.e. /dev/ad1s1)
    >>
    >>
    title FreeBSD
    root (hd0,1,a)
    >>
    Considering you have only one harddisk and two windows style (primary) partitions, if FreeBSD is on second partition or slice of that single harddisk, shouldn’t it be /dev/ad0s2, instead of /dev/ad1s1? Your grub entry is correct. ad1s1 is first slice of second harddisk not second slice of first harddisk.

  3. argv says on May 16th, 2009 at 5:44 am :

    If you know what which OS you will boot next… e.g. you work in BSD most of the time and boot to XP occasionally to do some things… there is another way.

    You simply move the boot flag (0×80) to the OS (partion) you want to boot.

    Each OS has it’s own tool(s) to do this safely and quickly.

    e.g.

    BSD –> fdisk -B

    XP –> ‘3parted.exe’ exefrom PLoS Linux site or tools from ‘the starman’ site

    Linux –> GNU fdisk or GNU parted

    This alternative method obviates the need for Grub and allows you to keep the Windows MBR unmolested. :)

  4. Ted Mittelstaedt says on March 20th, 2010 at 9:38 pm :

    Quick update to the last post:

    The Linux distro is PLoP, not PLoS

    The tool isnt’ 3parted.exe it is plppart32 and it can be separately downloaded
    from http://www.plop.at/en/windowstools.html

    There’s also a free trialware partition manager called Paragon partition Manager that while it has a lot of features disabled it does allow you to “set active” different partitions.

  5. Ted Mittelstaedt says on March 21st, 2010 at 12:06 pm :

    One more update,

    The plppart32 program works fine but you have to run it twice, once to remove the active flag from the windows partition and the second time to add the active flag to the FreeBSD partition.

    Also under FreeBSD the command is

    fdisk -a

    not fdisk -B, and also you must run the sysctl kern.geom command to set the MBR writable.

  6. Randy says on July 14th, 2010 at 7:06 am :

    Does FreeBSD do this automagically these days, or does this still have to be done manually?

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