While digging further into this I discovered that the UEFI install images boot up in Legacy BIOS mode, not in UEFI mode. Disabling Legacy BIOS boot on my system before trying to boot the install image resulted in not being able to boot up at all. So even though the image contains and EFI wedge it doesn’t seem to contain all the bits and pieces necessary to boot.
Guess I’ll have to dig a bit into this and see what’s necessary to duplicate this feat on my hard drive where I did the GPT/UEFI install.
