Hey guys,

I have a Z77X-UD5H rev1.1 with the latest modified BIOS as of this post (F16 mod8). I'm having an issue with booting this board up into an existing Windows 7 UEFI installation.

I can boot into the installation fine when I have CSM enabled in the BIOS. However, upon disabling CSM, I receive a "boot\BCD" error when trying to boot into Windows. Mind you, this is located on the EFI partition. I installed this copy of Windows with CSM enabled, but definitely made sure it was GPT/UEFI.

I've done some reading and found conflicting reports as to whether or not Windows 7 will boot with CSM off. From my research, I've learned that it mainly has to do with video drivers. I'm using a Gigabyte GTX 670 with the latest UEFI BIOS, so I'm thinking that shouldn't be a problem.

Mind you, I'm able to boot into OSX 10.9 with CSM off without any issues. The real question is - what is preventing me from booting into Windows 7 UEFI with CSM off?

Thanks.