These are the steps I used to replace LILO with GRUB as the boot manager after upgrading my kernel to v3.

Download directly and install:

wget http://slackware.osuosl.org/slackware-13.37/extra/grub/grub-0.97-i486-9.txz
installpkg grub-0.97-i486-9.txz

Then jump to Step 3 and make sure you skip Step 4.

  1. If you haven’t set any mirror for your slackpkg, you need to edit your mirror list:

    vim /etc/slackpkg/mirrors
    

    Add a mirror, for an example, I use the one from Oregon State University: http://slackware.osuosl.org/slackware-13.37/

    Do not forget the trailing /.

  2. Run the update:

    slackpkg update
    
  3. Remove LILO

    removepkg lilo
    
  4. Install GRUB

    slackpkg install grub
    
  5. Run configuration editor for GRUB (just like liloconfig):

    grubconfig
    

    This is my working config from /boot/grub/menu.lst

    # GRUB configuration file '/boot/grub/menu.lst'.
    # generated by 'grubconfig'.  Fri May 11 02:21:11 2012
    #
    # The backup copy of the MBR for drive '/dev/sda' is
    # here '/boot/grub/mbr.sda.1594'.  You can restore it like this.
    # dd if=mbr.sda.1594 of=/dev/sda bs=512 count=1
    #
    # Start GRUB global section
    #timeout 30
    #color light-gray/blue black/light-gray
    # End GRUB global section
    # Linux bootable partition config begins
      title slackware on (/dev/sda1)
      root (hd0,0)
      kernel /boot/vmlinuz root=/dev/sda1 ro vga=normal
      initrd /boot/initrd-3.2.13-smp
    # Linux bootable partition config ends
    title --- For help press 'c', type: 'help'
    root (hd0)
    title --- For usage examples, type: 'cat /boot/grub/grub.txt'
    root (hd0)
    

That’s it :)

References: