August 2, 2012
Looks over here – http://forums.macrumors.com/showthread.php?t=1325709. They are patching 32-bit boot.efi to make it loading 64-bit kernel. Obviously such functionality cant be added if it werent present at all. So they just disable the check/lock preventing it. ML on original macpro.
So, greedy Apple, can boot 64-bit kernel on all their macs with 64-bit cpu but decides not to!