I have an iMac (bought in 2011) and I recently upgraded it with Yosemite. I am trying to install Windows 7 on it via Bootcamp.
However, its optical drive does not work, so I chose the USB key solution using the trick of modifying the file info.plist of Bootcamp (type 'usb bootcamp youtube' in google to see a video of this trick).
So I follow the process religiously and end up with the classic and famous boring screen 'No bootable device -- insert boot disk and press any key'.
So I tried to use Unetbootin ( http://unetbootin.sourceforge.net ) to make my USB Key bootable, and tried to boot on it through the screen that appears when you maintain the Option key (Alt button) while starting the mac. Result: I never managed to have my Unetbootin-formatted USB key appear on this screen :(
I read some stuff about reFit ( http://refit.sourceforge.net ) and GParted, but I just don't know how to use them...
If someone managed to install Windows 7 on his/her iMac with Yosemite using a USB Key, please help me out!
Thanks everyone!
Pierreunderstand why I can't see the USB as a boot option.