8.7. How can I use the NT loader to boot FreeBSD?

The general idea is that you copy the first sector of your native root FreeBSD partition into a file in the DOS/NT partition. Assuming you name that file something like c:\bootsect.bsd (inspired by c:\bootsect.dos), you can then edit the c:\boot.ini file to come up with something like this:

        [boot loader]
        timeout=30
        default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
        [operating systems]
        multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Windows NT"
        C:\BOOTSECT.BSD="FreeBSD"
        C:\="DOS"
      

This procedure assumes that DOS, NT, FreeBSD, or whatever have been installed into their respective fdisk partitions on the same disk. In my case DOS & NT are in the first fdisk partition and FreeBSD is in the second. I also installed FreeBSD to boot from its native partition, not the disk MBR.

Mount a DOS-formatted floppy (if you've converted to NTFS) or the FAT partition, under, say, /mnt.

        dd if=/dev/rsd0a of=/mnt/bootsect.bsd bs=512 count=1
      

Reboot into DOS or NT. NTFS users copy the bootsect.bsd and/or the bootsect.lnx file from the floppy to C:\. Modify the attributes (permissions) on boot.ini with:

        attrib -s -r c:\boot.ini
      

Edit to add the appropriate entries from the example boot.ini above, and restore the attributes:

        attrib -r -s c:\boot.ini
      

If FreeBSD is booting from the MBR, restore it with the DOS ``fdisk'' command after you reconfigure them to boot from their native partitions.