+Depending on how the image is to be booted, the \-\-mbr option may also be
+necessary with extlinux.
+.IP \-\-squash
+Run mksquashfs against the final image using xz compression - requires
+squashfs-tools to be installed. The final file will have the .squashfs suffix.
+By default, mksquashfs is allowed to use all processors which may result
+in high load. Run mksquashfs separately if you need to control the number
+of processors used per run.
+.IP \-\-configure\-apt
+Use the specified mirror and distribution to create a suitable apt source inside
+the VM. Can be useful if debootstrap fails to create it automatically.
+.IP \-\-grub
+Disable extlinux installation and configure grub2 instead. grub2 will be added to
+the list of packages to install. update-grub will be called once the debootstrap is
+complete and grub-install will be called in the image.