I've been working on this for almost a week and it's driving me nuts. Here's the deal: My folks have a Mac Mini and I have a 2006 1,1 Mac Pro. I got a new MacBook Pro and have found little use for the tower around the house besides streaming iTunes to my Apple TV. My dad uses AutoCAD on the Mac Mini and it struggles a great deal. So I want to swap my tower for their mini. They are currently running Yosemite on the Mac Mini's internal HD which I cloned and attached to my MacBook Pro with an external HD dock. When I hold "option" to boot from the external so I can patch the boot.efi files I only get my MBP's internal, OS X Installer, and Recover disks as options, but NOT the Yosemite Boot disk. Am I missing something? I have tried on 2 machines, including the Mac Mini whose HD I replaced with an SSD and a fresh install, but have not been able to boot from the external. And, I cannot figure out how to get to the usr/standalone/i386 folder to replace the boot.efi file so I can boot directly from the drive in the tower. There are tons of sites with tons of information on "Fresh Installing" Yosemite in unsupported Macs but very limited to nonexistent on porting an already running drive into an unsupported Mac. Please help and thanks in advance. EDIT: Using this code: ‘open -a finder /volumes/volumename/usr/standalone/i386’ where ‘volumename’ is the name of the disk on which you’ve just installed Mavericks and ‘open -a finder /volumes/volumename/system/library/coreservices’. from this site: http://retrocosm.net/2014/01/04/mac-pro-11-and-mavericks/ I was able to replace the boot.efi files in both locations. I have removed all of the drives except the clone with altered boot.efi's and when I start the Mac I get the folder with the "?" The drive is not corrupt, because I can access the drive and it's contents from a different boot drive. It just won't boot. Again, thanks in advance.