Someone had reported that the method for using DISKPART did not work, but I have done this twice and it works remarkably well, and it's the only method I could find to create a Mac-Bootable Flash. I used TransMac on Windows 7 to restore the image file I had to the Flash Drive, it created a bootable Mac image on my flash drive. Dryden's Link, I was able to use the Diskpart command to clean and prep a GPT partition on a flash drive for an OSX Mavericks install image. I was never able to write a Mac installer image to my Flash Drive and have it bootable, unless I did it on a Mac. I know this question is old but it is still valid.