repair a FreeBSD install

[Manolis Kiagias]

Chad Perrin wrote:
> On Sun, Jun 03, 2007 at 02:34:28PM -0500, Kevin Kinsey wrote:
>   
>> Chad Perrin wrote:
>>     
>>> Someone I know tried installing Slackware on a Thinkpad R52 to create a
>>> triple-boot system (MS Windows and FreeBSD 6.2 as the other two, already
>>> present on the system).  The Slackware install didn't get very far (the
>>> installer is less than helpful -- wouldn't recognize a swap partition at
>>> all), but apparently it got far enough to break the FreeBSD install.
>>>
>>> Any tips, hints, and suggestions about how exactly to go about fixing
>>> the FreeBSD install (without overwriting the home partition and losing
>>> the installed system configuration to minimize time lost getting things
>>> back to "normal") would be appreciated.  Thanks in advance.
>>>       
>> What exactly is broken in the FBSD installation?  Just won't
>> find enough bootstrap stuff to boot?
>>     
>
> Shortly after the aborted Slackware install, the FreeBSD bootloader
> still loaded, but chosing the FreeBSD option would just cause it to hang
> rather than booting up the OS.  Since then, Debian has been installed in
> the free space on the drive, with GRUB installed as the new bootloader,
> and it doesn't list the FreeBSD option as existing at all.
>
>
> <SNIP>
You can use the grub bootloader to load freebsd (assuming that nothing
is damaged in the freebsd slice itself, and I believe it is intact in
your case)
It's been some time since I've done this myself (I am no longer dual
booting FreeBSD on this machine), but I'll try to be as accurate as
possible.
Start your system, when it gets to the grub loader press "c" to get to
the grub command line.
Do you know what your freebsd slice is? Even if you don't, you can get
this info from fdisk -l from debian. Or you could try searching in the
command line.
Type something like:

root (hd0,2,a)

that is assuming your freebsd slice is hda3 (or sda3) - grub numbering
starts from 0
If you are not sure about the number try others like root (hd0,3,a) and
so on. You will know when you hit the correct partition, since it will say:
Filesystem type is UFS, partition type ... (something similar)
Then type
kernel /boot/loader
and then type
boot
If you get into freebsd successfully, you can then add all the above
instructions in the grub configuration file (normally in
/boot/grub/menu.lst in your linux system)
Hope this helps.