MDT 2013 - Gen2 VM / UEFI

Is it compulsory to have UEFI partitions when creating a image with Gen2 VM? I am trying to build a Win 8.1 for virtual master image and do not require the UEFI partition.

When I remove the 'Boot (EFI)' from 'Format and Partition Disk' I get following error in the BDD log:

FAILURE ( 5615 ): False: Boot Drive was not found, required? LTIApply 1/8/2019 12:27:45 PM 0 (0x0000)
Event 41002 sent: FAILURE ( 5615 ): False: Boot Drive was not found, required? LTIApply 1/8/2019 12:27:45 PM 0 (0x0000)