I previously posted an article on Installing Windows 7 or Windows Server 2008 R2 from USB Stick. I’ve been using this process for a while and it’s worked beautifully! However, we recently got in a PowerEdge R510 (12x drive bays) and our RAID10 array is larger than 2TB, so I ran into the 2GB MBR limit.

If you Google around, TONS of people run into problems with this. Ultimately, the solution is different for every EFI implementation. With Dell’s uEFI v2.1 (uEFI before v2.0 does not work with Windows, FYI), the solution was rather simple but me and a team of support engineers at Dell spent a better part of half a day to figure it out.

  1. First of all, the USB stick MUST be formatted as a FAT32 drive. NTFS will not work!
  2. Next, follow my instructions from Installing Windows 7 or Windows Server 2008 R2 from USB Stick. This will get you a USB stick that will work for non-GPT installs, but we need to modify it for EFI installs using Dell’s uEFI implementation.
  3. Now, here’s the part that wasted so much of our time! On your USB stick, go into the H:\efi\microsoft** folder and copy the *boot folder into the *H:\efi** folder.
  4. Next, go into an existing install of Windows 2008 R2 and copy the bootmgfw.efi file out of c:\Windows\Boot\EFI** into the USB stick’s *H:\efi\boot* folder but rename it to **BOOTx64.EFI (not case sensitive).

At this point, the USB drive should be bootable to Dell’s uEFI v2.1 (and likely other versions) in a way that makes Windows happy!

These steps should also work for Windows Vista x64 SP1 (and newer), Windows 7 x64, and Windows Server 2008 x64 SP1 (and newer). If you have a 32-bit version of Windows, then give up (or really, upgrade to a 64-bit OS, are you crazy?!).