by lunarg on July 7th 2015, at 14:21

It may be useful to know whether your Mac has a 32-bit or 64-bit EFI. This can be done by running the following command from an OSX Terminal (can run from the installer or recovery partition):

ioreg -l -p IODeviceTree | grep firmware-abi

This should return something like the following:

• For 32-bit EFI:  | | "firmware-abi" = <"EFI32">
• For 64-bit EFI:  | | "firmware-abi" = <"EFI64">