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I'm the Windows guy on our team, and the Mac guy doesn't have an answer for me, so I'm hoping someone here specializes in both enough to help me out.

To be very terse, I have a custom WinPE image to deploy to the Macs which installs our Windows .wim on first boot. It all works great, except putting the very first WinPE or Windows image on the device. If I overwrite an existing working Windows install (even after a diskpart clean and format), it works just fine. If I have Boot Camp create my partition from scratch and deploy my Windows or WinPE image that way, it doesn't show up in the boot menu at all. I've ran bootsect /nt60 c:, deployed a proper BCD store, and set the partition as active which should be enough to boot off of it. I've even tried bless /dev/disk0s4 --legacy from the Mac side (though I'm not totally sure that does what I think it does), and the Mac just won't give me the option to boot from that partition.

Is there something else I need to do on the Mac or Windows side to flag this partition as bootable to UEFI?

Also just to make sure I'm being understood correctly: If I create a partition via Boot Camp, boot to a WinPE CD, imagex /apply X:\windows.wim 1, bootsect /nt60 c:, bcdboot c:\windows, then I've created a valid Windows install on the second partition yet UEFI doesn't allow me the option to boot from it and that's what I'm trying to fix.

share|improve this question
Do you need to do a legacy boot (BIOS emulation), or can you use (U)EFI for booting? I manually set up an UEFI-booting Windows 8.1, and that's working fine. – fefrei Dec 28 '13 at 14:26

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