Snow Leopard 64 bits mode (EFI64 Firmware)

Question

How do I get the EFI64 firmware on my iMac 20" (late 2006) with Intel Core 2 Duo?

Answer 1

As there is no EFI64 firmware update, the only option left to know if you have a 64 bits EFI is to run the following command:

ioreg -l -p IODeviceTree | grep firmware-abi

If the result is "firmware-abi" = <"EFI64">, then you have a 64 bits comptabible EFI. If the result is "firmware-abi" = <"EFI32">, then you don't have a 64 bits compatible EFI.

This parameter only affects the kernel load by Snow Leopard. You can still run 64 bits applications, bu the kernel will run as 32 bits.

Answer 2

The is no EFI64 firmware upgrade available. Thus, you have to stay with the 32-bit Snow Leopard kernel (but you can use 64-bit Apps anyway).