delete EFI partition with Diskpart
Step 1. Hit "Windows Key + R to open the run dialogue
box, enter "diskpart" and click "OK" to open a black command prompt window.
Step 2. Type "list disk" to display all the disks of your
computer. Type "select disk n" to identify which disk you need to work with.
Here n stands for the disk letter.
Step 3. Type "list partition" to display all the volumes
on the hard drive. Type "select partition n" to identify which partition you
want to remove. Here n stands for the volume letter.
Step 4. Type "delete partition override" to remove the
EFI partition. Finally, type "exit" to close the windows when you receive the
message says, DiskPart successfully deleted the selected partition".