Hi.
Can anyone help to undersatnd, with some explanations, if 10.6 Snow Leopard can run on a MacBook Pro 13" Late 2009 (MachineID MacBookPro5,5) in 64bit mode from boot?

I read netkas's tip and followed his instruction to check if EFI are 64bit or not (yes, they are) but in the compatibility list this model of Mac is excluded.

So I don't know if really need to apply the patch to com.apple.Boot.plist file or that's not necessary.

*IF* you need to change anything to boot into 64-bit mode, it would be to run the following command in your terminal:

sudo nvram boot-args="arch=x86_64"

From the look of it, Apple will only be doing a 64-bit Kernel for their computers by default for their xserves and Nahlem Mac Pros.

Although, anything could change between 432 and the GM. (Yea, I still refuse to believe that 432 *is* the GM, but that is a discussion for another time and place.)

~Adrian

I found this:

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• How to check Whether your Mac has the 32-bit EFI or 64-bit EFI :
When you are reading this i m sure you understand that you can boot into full 64bit mode if your Mac has 64-bit EFI. Also note that Apple disabled 64-bit kernel support for any Macbooks, even with 64-bit EFI. So if you have an older Mac Pro, iMac and you wants to check Whether your Mac has the 32-bit EFI or 64-bit EFI just enter the following command in Terminal.

ioreg -l -p IODeviceTree | grep firmware-abi

And you’ll get the answer either “EFI32″ or “EFI64.”
• How to boot 64-bit Kernel by default at every boot : Though you have a EFI64 and 64-bit compatible Mac your install will boot into 32-bit kernel by default. Thanx to Netkas for highlighting a trick to change default boot kernel. All you have to do is edit a string file in com.apple.Boot.plist To edit boot.plist navigate to /Library/Preferences/SystemConfiguration/com.apple.Boot.plist and open the boot.plist with text editor and find the following string.

<key>Kernel Flags
</key><string></string>

and change it to

<key>Kernel Flags</key>

<string>arch=x86_64</string>

That’s it, now your installation will boot in to 64-bit kernel mode every time. So no more holding down the ‘6′ and ‘4′ keys during boot. Just in case if you need to boot the 32-bit kernel just hold down the ‘3′ and ‘2′ keys during boot.

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Check if you running in 32 or 64 bits kernel mode:

open Terminal and type "uname -a" (without quotes). It should return something that ends in either i386 (32-bit) or x86_64 (64 bit)
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Well.
I'll wait for Snow Leopard, then after a clean install from a zero-formatted hard drive I'll check again wich kernel it uses by default.
In case I'll apply a patch to Boot file to load the 64bit kernel at boot.

Thanks guys!

Hi!

It´s funny the terminal of my Macbook Air replies “EFI64″ on the command "
ioreg -l -p IODeviceTree | grep firmware-abi", so it looks like I have a 64-bit compatible Mac...

I carried on and patched the com.apple.Boot.plist to <key>Kernel Flags</key>

<string>arch=x86_64</string>, but without bigger success... Typing the command "uname -a" results with the answer "...i386" = 32-bit!

What´s wrong people?

=) alex

I'm in the same boat...I can't get my Air (1,1) to boot the 64bit kernel...

Have you resolved this issue?

The Macbook Air (1,1) has the Intel GMA X3100 graphics card, which unfortunately only has a 32-bit driver available at this time.

If you were to boot into the 64-bit kernel, you would be loosing the ability to see anything on your screen.

Guess you are stuck with a 32-bit kernel and 64-bit apps on your system which is only capable of supporting the 2GB RAM that is soldered to your logic board.

Sorry, dude.

~Adrian

Hopefully in the coming updates (10.6.1, 10.6.2) 64-bit drivers will be available for the components in the 2009 Mac mini, MacBook and MacBook air.

I hope Apple doesn't hold back in releasing the remaining 64-bit drivers for machines that have 64-bit EFI.

64bit has been disabled by default on all MBP3,1 models and earlier plus all models of macbooks (unibody or mbp 13")... Hope they enable the 64bit for all those machines in 10.6.1 or else i'm not going for snow leo at all...

Thanks for the input