Ok, lets clear this one up and go on with the thread;
1.
There is no flashing of any EFI involved. I dont believe there is any re-writing of any boot ROMs that reside on any critical hardware items.
2. Kernel panics and boot crashes
are almost always due to people not following the instructions correctly. (They are not hard). Usually the problems arise at the start of the related threads whilst the code is being debugged and put together.
3. Most people should have a backup, its sensible. The thread is primarily for Mac Pros which mean multiple drives. All you need to test is a HDD of 20GB or more.
eBay Uk would see you with one for about £6. Thats not a huge outlay.
What these people suffering crashed should have done is bought one of these drives and installed it on there and tested, those that use a production machine are lets say, less sensible.
4. All you need is a capable graphics card and youre set, you can even use an unflashed PC one.
I can tell you from personal experience that once you put some work in to understand it youre golden.
There is probably one file to replace in the System folder and two plists to modify, after that you can boot Yosemite. One of those files is the
PlatformSupport.plist and if you have a look at yours which is located in /System/Library/CoreServices and you will see entries like below, (this is
Apple making the installer check if your machine is what they 'consider to be supported',
not the hardware flaking out);
<string>Mac-4B7AC7E43945597E</string>
<string>Mac-F22C89C8</string>
<string>Mac-F22587A1</string>
<string>Mac-942459F5819B171B</string>
<string>Mac-F42388C8</string>
<string>Mac-F223BEC8</string>
<string>Mac-F4238CC8</string>
<string>Mac-F222BEC8</string>
<string>Mac-4BC72D62AD45599E</string>
<string>Mac-F2208EC8</string>
<string>Mac-66F35F19FE2A0D05</string>
<string>Mac-F4238BC8</string>
<string>Mac-189A3D4F975D5FFC</string>
Basically if your Mac is on the list you have a green light. This is similar to Siri not working on the iPhone4, ie an artificial limitation set by the powers in Cupertino. The worst thing about it is that at one time even Apple had it working. IIRC the first Dev Preview of Mountain Lion
did natively support the early Mac Pro. Apple removed it for the later betas.
Michael, have a
look at the threads before posting back.