Comment Re:Diagnostics, system configuration, etc (Score 1) 216
The problem with having a totally inaccessible one like Apple does is that if anything goes wrong or you need to change something, well then you are fucked.
How is the Mac EFI "inaccessible"? Just put your EFI extensions (for example rEFIt or an EFI shell) on any disk with an EFI partition or a HFS+ volume with the appropriate blessings. The disk can be CD, USB or FireWire.
Of course, it is not often you need to do this, since it's very rare to see a Mac that doesn't boot OS X from any device. In out Mac cluster at work, we can almost always netboot the machine and diagnose from there, when the OS X install DVD won't boot.