if [[ $(blockdev --getsize64 ${boot_disk}4) == 8388608 ]]; then
# old partition scheme
grub_dev=${boot_disk}4
-else
+elif [[ $(blockdev --getsize64 ${boot_disk}5) == 8388608 ]]; then
grub_dev=${boot_disk}5
+else
+ grub_dev=${boot_disk}7
fi
e mount $grub_dev $mount_point