Microsoft has released an update that removes the "Windows 8.1 SecureBoot isn't configured correctly" watermark in Windows 8.1
Just to restate my main question:
Will Dell release a UEFI compliant video card BIOS update for the NVIDIA GTX 690 that I purchased with my Aurora R4 from Dell?
Other NVIDIA card vendors have provided a video card BIOS update for the GTX 690 NVIDIA card that they sell that works with Secure Boot. I do not think NVIDIA will provide this directly, even though my card shows the subvendor is NVIDIA and not Dell.
What i would do is find out who actually makes that card for dell someone has to make it and brand it dell i don't think they make these i could be wrong. But i would be calling and asking dell hay who makes the cards for you, if they say nvidia say know thats the chip who makes the card hardware.
I chatted online with NVIDIA tech last night. He said that they do not manufacture any of the cards; the card is manufactured by Dell and that they are just the designers. Of course, as you say, most things are sub-contracted out in some way by large companies.
If you read the BIOS ROM from the Dell GTX 690 card, it says, "Version 80.04.1E.00.13 Copyright (C) 1996-2012 NVIDIA Corp". This suggests that NVIDIA wrote the BIOS. Perhaps the card vendors edit these ROMs just enough to put their subvendor ID in or maybe they do more editing to ensure compatibility with their motherboards.
In any event, NVIDIA says it is up to Dell to do what ASUS, EVGA and possibly other card vendors have done and provide a GTX 690 video card BIOS that works with Secure Boot.
Nvflash has an option to write only to the UEFI portion of the card if you have a UEFI file "Update only the UEFI portion of the ROM image from <filename>". Maybe that is all that is needed for this card to be recognized to work with Secure Boot?
Today Dell replaced my NVIDIA GTX-690, along with my motherboard and memory under warranty (would not boot past Alienware splash screen -- F2, F12 did nothing).
Now I finally am able to enable Secure Boot, as the GTX-690 they sent has a UEFI-compatible BIOS, while the one I got with my new Aurora-R4 did not.
For reference, the new NVIDIA GTX-690 has Video BIOS version: 80.04.1E.00.1F. And work with Secure Boot.