Came to say renaming EFI- to EFI (without the trailing - ) worked for me. Also resetting the UEFI keys helped on subsequent reboots. What's going on with the USB creator app? I just don't get it.
Tried same settings as @wgstarks and still failing.
I'm thinking of downgrading to 6.9.x because every time a new 6.1x version is launched something gets broken.