If a system is in UEFI mode it must use the UEFI DETech disk. Although you can boot to the MBR based DETech when running in UEFI mode just as you can boot to any other MBR boot disk while running in UEFI mode; however, the disk will not allow you to perform many of the functions as the Preboot File System is entirely different or UEFI.
The likley cause of the failure to boot to the UEFI DETech disk is Secure Boot was not disabled on the UEFI Setup Screen (BIOS). Because the UEFI DETech efi file is not signed, secure boot will not allow the efi file to run thus the system will not "boot" to UEFI DETech.
Secure Boot is actually disabled. I did the usually format 'volume' /FS:FAT32 /V:EETech and did the standard copy the EpeTechEfi.efi over in following with the updated name "\EFI\Boot\BootX64.efi" but no luck.