Nope. It's not UDF. The Windows ISO has the bootmgfw.efi file in the El-Torrito image which Tiano Core can read. The bootmgfw.efi file understands UDF/iso9660.If you want to test, make your own FAT32 USB stick by copying all the files from the DVD and add bootmgfw.efi to /EFI/boot/boox64.efi and /EFI/Microsoft/Boot/bootmgfw.efi on the USB Stick.Windows 7 doesn't work because it requires a VGA Option ROM to be POST-ed (yes, Windows wants a BIOS component, the int10h in a BIOS-less firmware) and a GOP/UGA driver that also supports 1024x768 and 800x600 next to the native resolutions for the wavy flag part (before the accelerated graphics driver is used).