10.6: How to boot into the 64-bit kernel

Sep 15, '09 07:30:02AM

Contributed by: Anonymous

Users who want to run the new 64-bit kernel on late-model Macs (pretty much anything released after early 2008) can do so by booting with the 6 and 4 keys held down. If you're wondering whether your Mac has a 64-bit EFI firmware, you can type this command in Terminal:

ioreg -l -p IODeviceTree | grep firmware-abi
The response will identify the machine as either having 32-bit or 64-bit EFI. I found this tidbit in this article on AppleInsider.

[robg adds: Note that if you boot in 64-bit kernel mode, you may have unexpected oddities. In my case, web pages that contained Flash animations would cause Firefox to quit. Rebooting in 32-bit mode (hold 3 and 2 during boot) solved the problem. Unless you have a definitive need for the 64-bit kernel, I'd recommend sticking with 32-bit mode for now.]

Comments (24)


Mac OS X Hints
http://hints.macworld.com/article.php?story=20090902100235176