Below are the menu entries for a grub.cfg that should work with the mini.iso (although I haven't tested). Just download the correct version of the mini.iso (32 or 64) from here http://cdimage.ubuntu.com/netboot/precise/ and use the ofboot.b and grub.img files from post #1.

Code:
menuentry "Install" {
  set root=(grubdevice,1)
  set isofile="/mini.iso"
  loopback loop $isofile 
  linux (loop)/vmlinux root=/dev/ram ro --
  initrd (loop)/initrd.gz
}
   
menuentry "Expert" {
  set root=(grubdevice,1)
  set isofile="/mini.iso"
  loopback loop $isofile 
  linux (loop)/vmlinux root=/dev/ram priority=low ro --
  initrd (loop)/initrd.gz
}
   
menuentry "Cli" {
  set root=(grubdevice,1)
  set isofile="/mini.iso"
  loopback loop $isofile 
  linux (loop)/vmlinux root=/dev/ram tasks=standard pkgsel/language-pack-patterns= pkgsel/install-language-support=false ro --
  initrd (loop)/initrd.gz
}

menuentry "Cli-expert" {
  set root=(grubdevice,1)
  set isofile="/mini.iso"
  loopback loop $isofile 
  linux (loop)/vmlinux root=/dev/ram tasks=standard pkgsel/language-pack-patterns= pkgsel/install-language-support=false priority=low ro --
  initrd (loop)/initrd.gz
}
 
menuentry "Rescue" {
  set root=(grubdevice,1)
  set isofile="/mini.iso"
  loopback loop $isofile 
  linux (loop)/vmlinux root=/dev/ram rescue/enable=true ro --
  initrd (loop)/initrd.gz
}