As I can see from "Extra" menu there are several ways to include a non-natively supported ISO:
RAM GRUB Extra mode
GRUB Extra mode
RAW MEMDISK Extra mode
MEMDISK Extra mode
Hmm, what are the differences between them?
Assume I want to add a new unlisted foobar.ISO.
How do I find out which mode is required for this new iso?
Is there always exactly ONE mode which is possible or can I select among several (all?) of the modes?
Peter