User with any of the M14x R2 / M17x R4 / M18x R2 notebooks with a current BIOS have reported issues when using the Secure Boot / Fast Boot options in combination with the dedicated Nvidia / AMD GPU.("Can't detect MXM card GOP driver" in case of the R4 / M18x R2)
The reason for this is simple - Dell never provided a vbios update which includes the necessary graphic drivers to make those feature work. The only UEFI compliant drivers in the system have been the ones of the Intel HD iGP.
A very big failure on Dell's side if you ask me, especially since this has been reported here and in other forums as well on the dell community site and it was said that people would look into this... absolutely nothing happened.Not that this really surprises me... looking at the latest BIOS releases and also at the behavior regarding release notes for such updates. Seems we need to look for the updates ourselves.
Anyway, Dell actually ships the very latest systems with updated vbios on the dedicated GPUs.
Attached to this post you can find a new vbios for the Nvidia GTX 680m, 660m as well as the AMD 7970m. Both include the required UEFI drivers, and should therefor fix this issue.
Thanks @Zyron for the 680m vbios.
I don't have a version for the 675m so far, so if anyone has an updated vbios for that card, please let me know or post it.
Flashing instructions for Nvidia: http://forum.techinferno.com/general-notebook-discussions/2166-%5Bguide%5D-nvidia-vbios-flashing.html
Flashing instructions for AMD: http://forum.techinferno.com/general-notebook-discussions/1738-%5Bguide%5D-amd-vbios-flashing.html
As for the M14x R2, a new, yet unreleased BIOS (A10) has made it's way to the web. You can find it here: http://forum.techinferno.com/alienware-m14x/2655-%5Bm14x-r2%5D-a10-bios-fixes-uefi-issues-nvidia-card.html
Check the third post. Also I took a quick look at it and wrote down the most important changes (post #4).
EDIT: M14x R2 BIOS A10 is now officially available on the Dell drivers site.
M14x R2-Dell GTX 660m - 80.07.39.00.0F.zip
M14x R2-Dell GTX 680m - 80.04.5B.00.02.zip
M14x R2-Dell 7970m - 015.022.000.001.000000.C42904A1.119.zip
M14x R2-Dell 675m - 70.24.4E.00.10.zip
M17x R4-Dell GTX 660m - 80.07.39.00.0F.zip
M17x R4-Dell GTX 680m - 80.04.5B.00.02.zip
M17x R4-Dell 7970m - 015.022.000.001.000000.C42904A1.119.zip
M17x R4-Dell 675m - 70.24.4E.00.10.zip
M18x R2-Dell GTX 660m - 80.07.39.00.0F.zip
M18x R2-Dell GTX 680m - 80.04.5B.00.02.zip
M18x R2-Dell 7970m - 015.022.000.001.000000.C42904A1.119.zip
M18x R2-Dell 675m - 70.24.4E.00.10.zip