Just as a matter of trivia and amusement, Fedora EFI System partitions
are FAT16. Windows and OS X create them as FAT32.
https://bugzilla.redhat.com/show_bug.cgi?id=1046577
I think since the EFI file system is actually a frozen in time FAT
implementation that shouldn't ever change (for compatibility reasons)
mkdofs probably needs something like an -e flag to explicitly create
EFI file systems per the spec.
Chris Murphy