Comment 3 for bug 601616

Hello, assuming you're running on PC, add this entry to 40_custom:

menuentry "Mac OS X Snow Leopard" --class macosx --class os {
          insmod hfsplus
          insmod part_gpt
          search --file --set=root /boot
          multiboot /boot
}

then

sudo update-burg

now you can at least chainload to another boot manager..
Hope it helps.