Your post gave me just enough information to finally figure this out, so thank you.

I was misunderstanding how EFI boot works in general (I'm a little bit TOO old school sometimes), and this got me over the final hump. The link was very helpful. I'm just so used to using the easy-button in the lifecycle controller, the non-standard approach was throwing me off.

For anyone else reading, if you are trying to do non-Dell device firmware updates such as Intel NIC's in efi file format, go to the link above and get the "shell.efi" file, and put in in a directory on your fat32 formatted USB stick like this: /efi/boot/Shell.efi, then rename the file to Boot64.efi. When done, you should have  /efi/boot/Boot64.efi.  In addition, copy any firmware files or programs you may need into a separate directory on the same usb stick for use after you get the shell running.

Plugin your USB stick to the machine you are working with and set your BIOS to boot UEFI mode, then on post, press F11 to enter the one shot UEFI boot manager. Once there, select your USB stick from the list, and the machine should boot into the EFI shell from the USB stick. After that, just google for the commands that the EFI shell will accept.

Those were my steps used on R730, R730XD,, and R620 equipment. 

Also to note, I tried using the remote mapping of the USB stick using the iDRAC virtual media and updated 2 units remotely and it works fine. Just keep in mind that in the F11 boot menu, the "virtual floppy" will be the device you select as there will be no remote USB in the list. I would also not try to update firmware remotely unless you have a rock-solid and reliable network connection... any interruption in the flashing process can and probably will render the device dead.

Thanks again Martin!