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Grub Bootloader on FreeBSD

by <Jiafu He>jiafu_he at, 05/18/2004

This mini-howto is written as a dummy introduction on how to get, install, setup and use GNU/Grub bootloader on FreeBSD. If you need more detailed information, go read the Grub mannual at Note: UFS2 is supported starting from the verion Grub-0.94_3.

1. Obtaining Grub files:

  To use Grub on FreeBSD UFS2, you need files "stage1", "stage2" and 
  "ufs2_stage1_5". To handle other types of file systems, you need 
  other stage 1.5 files like "ffs_stage1_5", "e2fs_stage1_5", or 
  "fat_stage1_5" etc. 
  You can obtain the files from either
  i. the GNU/Grub website
  ii. or FreeBSD Grub port. Grub-0.94_3 requires freebsd 5.2.1 or 
     current. To install Grub-0.94_3, do the following:
  #cd /usr/ports/sysutils/grub  /* go to the grub freebsd port dir */
  #make install clean    /* install it */
  If all goes well, the Grub files are generated in directory
  /usr/local/share/grub/i386-freebsd/ and the executable "grub" is 
  installed under /usr/local/sbin/

2. Installing Grub on UFS2 partition:

  i. Create /boot/grub/ directory (or alternatively /grub/) on your HD
     and copy files in it:
  #cd /boot;mkdir grub
  #cp -Rf /usr/local/share/grub/i386-freebsd grub
  Make sure at least files "stage1" and "stage2" are under /boot/grub/. To be 
  complete, the pertinent stage 1.5 file (here "ufs2_stage1_5") is also needed. 
  ii. Create Grub boot floppy. You can either
    a. using "dd" (recommended):
    #dd if=stage1 of=/dev/fd0 bs=512 count=1 /* stage1 to block #1 */ 
    1+0 records in
    1+0 records out
    #dd if=stage2 of=/dev/fd0 bs=512 seek=1 /* stage2 starting from block #2 */
    153+1 records in
    153+1 records out
    b. or alternatively using Grub "setup" under FreeBSD:
    #fdformat -f1440 /dev/fd0  /* low level format the floppy if you want to */
    #newfs -LGrubBoot -O1 /dev/fd0 /* format into UFS1 */
    #mount /dev/fd0 /mnt
    #mkdir /mnt/boot
    #cp -Rf /usr/local/share/grub/i386-freebsd /mnt/boot/grub
    #touch /mnt/boot/grub/menu.lst /* touch and edit menu.lst, see step 3 */
    #umount /mnt
    grub> device (fd0) /dev/fd0  /* set the device map */
    grub> root (fd0)
     Filesystem type is ffs, using whole disk
    grub> find /boot/grub/stage1 /* verify whether the required files are there */
    grub> setup (fd0) /* setup the floppy */
     Checking if "/boot/grub/stage1" exists... yes
     Checking if "/boot/grub/stage2" exists... yes
     Checking if "/boot/grub/ffs_stage1_5" exists... yes
     Running "embed /boot/grub/ffs_stage1_5 (fd0)"... failed (this is not fatal) 
     Running "embed /boot/grub/ffs_stage1_5 (fd0)"... failed (this is not fatal)
     Running "install /boot/grub/stage1 (fd0) /boot/grub/stage2 p /boot/grub/menu.lst "
     ... succeeded

3. Touch and edit "/boot/grub/menu.lst". An example is given below, assuming that

    - partition 0: Windows XP; 
    - partition 1: FreeBSD;
    - partition 2: Linux.
  default saved  # boot the last selection. Work together with savedefault below
  timeout 10  # timeout 10 seconds
  password --md5 $1$rEjBN0$0J06NigS.2ImTaipPOh0w/ # md5 passwd encryption: "testgrub" 
  # Boot Windows XP. You have to chainloading.
  title Windows XP Professional  # display boot title on the Grub prompt
  root (hd0,0)  # set the root device or partition
  makeactive  # set the partition active so that next time it can be automatically 
              # booted after timing-out 
  chainloader +1  # Here we have to chainload 
  savedefault  # save this selection as the default for next bootstrap 
  # Boot FreeBSD
  title FreeBSD 5.1_p16
  root (hd0,1,a)
  kernel /boot/loader  # specify the kernel or kernel loader
  # Boot Redhat Linux
  title Redhat Linux
  root (hd0,2)
  kernel /boot/vmlinuz-2.4.18-14smp ro root=LABEL=/ hdc=ide-scsi
  initrd /boot/initrd-2.4.18-14smp.img
  # Install Grub on Slice 1 (the FreeBSD partition)
  title Install Grub on FreeBSD (Slice 1)
  root (hd0,1,a)
  setup (hd0)

4. Install Grub to MBR on your hard disk (using grub native way):

  i. Boot the machine using the floppy just created;
  ii. on the Grub menu screen, you can either make use of the last menu entry 
      (see menu.lst above) or do the following:
     (Grub menu screen)
     p  # password is needed since the password line is in config file.
      password: testgrub
     c  # enter command prompt
     Then you enter the command prompt:
     grub> find /boot/grub/stage1  /* find which partition has Grub files */
     (hd0,1,a)  /* it will display the found parition */
     grub> root (hd0,1,a)
      Filesystem type is ufs2, partition type 0xa5
     grub> setup (hd0)  /* install Grub in MBR */
      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)"... 16 sectors embeded.
      Running "install /boot/grub/stage1 (hd0) (hd0)1+16 p 
      (hd0,1,a)/boot/grub/stage2 /boot/grub/menu.lst"... succeeded

5. Finally how to generate md5-encrypted password:

  Enter any Grub command prompt:
  grub> md5crypt  /* call the md5 password encryption utility */
   password: yourDesiredPassword  /* passwd are replaced by same number of "*" */
   EncryptedPassword  /* encrypted password is returned here, put it in config file */
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