You can use bcdboot.exe
to install the Windows UEFI bootloader to an available FAT32 partition: https://technet.microsoft.com/en-us/library/dd744347%28v=ws.10%29.aspx
Assume I:
is available to be the EFI System Partition: bcdboot.exe H:\Windows /s I: /f UEFI
No MBR to GPT conversion necessary, as long as your UEFI is standard-conforming enough.