Windows 10 install on mid 2010 Mac Pro - "EFI boot" is not in startup manager I have been working towards installing Windows 10 on my mid-2010 Mac Pro and have been using the following thread as a guide: said thread. I've formatted both my BOOTCAMP volume (where I plan on installing Windows), and the USB drive being used to boot from, to ExFat. As of now, the Windows 10 ISO and the Windows support software has been mounted and copied onto my BOOTCAMP volume, and I've modified the .xml filename as well as disabled the ability to EFI boot from the BOOTCAMP volume. I've also copied the same content (Windows 10 ISO, Windows support software), except here I didn't disable the ability to EFI boot. I've basically made it to step 10 in the thread I was following.

The problem occurs when I reboot my computer. I do so by holding down the option key during startup to access the Startup Manager. I expect to see EFI boot as an option to select and boot from, but my USB (EFI boot) is not there. The only options I have are my internal drives and the Recovery drive, but no USB or EFI boot option. I've gone back to the guide in order to ensure I've done everything right, but can't find a reason for why I can't boot from my USB drive - maybe the ExFat partitioning scheme is wrong for this process? 

Any insight would be greatly appreciated as I've been working on this for a few days now and would love to find a solution. 

Thank you so much in advance.
What can I say. If your Mac will not boot, then that is that. My 2011 iMac could boot Windows this way after a High Sierra installer update to the Mac's firmware. I assumed that all Macs would be able to boot this way after installing either High Sierra or Mojave. Either I am wrong or you made a mistake. 

When I originally posted this answer, the instructions FAT32 formatted the drives. This was changed to ExFAT after the October 2018 release of Windows 10. This ISO contains a file that exceeds FAT32 formatted drive limit of 4 GB per file. The April 2018 update does not have this problem.

If you can not get Windows installed using the method in your linked thread, then consider trying one of the older more complex methods. For example, see Installing Windows 7 or 10 Pro 64 bit without DVD or Flash Drive.