Hi, we just received a bunch of Dell E7240 ultrabooks and are tasked with getting Windows 8.1 loaded on them via SCCM 2012 r2. There is currently no option to PXE, I just get "Windows Boot Manager" or "UEFI: My SSD". I checked for passwords, and no passwords were set so I turned off Secure Boot and (after trying UEFI IPv4 with partitioning failures) turned on Legacy Mode. This allowed PXE using UEFI IPV4 as well as legacy boot to the onboard NIC, great! The partitioning I had set up for our Surface Pros did not allow the Dell E7240 to detect the OS once the UEFI selection was applied. So I tried BIOS configured partitioning and this does work fine.
Now, I don't want to turn off secure boot and UEFI on every one of our ultrabooks. So I tried to put this legacy mode ultrabook back into secure boot for further testing and now it has a * next to "Change Boot Mode Settings" and prompts me for a password. I've tried all manner of passwords from no password (press enter) to admin, administrator, password, etc and none will let me put it back in Secure Boot. I consider it a lost cause for now.
So I grabbed a 2nd ultrabook and am testing on this one now. Is there some kind of special key i have to press or setting to configure that will let me use my existing SCCM UEFI enabled (and tested) task sequence to image these ultrabooks or am I stuck taking them all out of secure boot, putting them in legacy mode, and using a basic BIOS/MBR partitioning setup?