I'm trying to mount a UDF ISO image on loopback to chainload from it. However, the problem is that the image doubles as an ISO9660 image. This means that by default, grub mounts it as an ISO9660, and so all I have access to is the redme.txt file on the ISO saying that I need UDF support. I have seen in several places that grub supports UDF filesystems, but I don't know how to *force* this image to be mounted as UDF. How would I do that?