Booting Mountain Lion in 32-bit

Goranberdal,

I found this answer on MacRumors, although I don't know how to do this exactly. Maybe someone on here can help us with the instructions.

Just add arch=i386 in to boot.plist and reboot.

OS X: Starting up with the 32-bit or 64-bit kernel

http://support.apple.com/kb/ht3773

As I understand it, the instructions just posted do not work on Mountain Lion. Holding down the 2 & 3 no longer work for sure. I've done lots of research and found lots of other people with the same issue. I believe the support article you posted applies to all version up to Mountain Lion. If anyone knows otherwise, please chime in.

ML is strickly 64 bit. https://discussions.apple.com/thread/4170904?start=0&tstart=0

goranberdal wrote:

Does anyone know if it's possible to boot OS X Mountain Lion in 32-bit?

I'm currently running OS X Lion v. 10.7.4, but considering an upgrade. I need to boot the system in 32-bit to get my external sound card working.

Better stick with with your OS X Lion v. 10.7.4.

I guess this is a truism Mountain Lion is 64 bit only. The KB reference above is outdated

The efi.boot file in the install disk contains this string; "Unsupported 32-bit-only CPU."

Not only is it x64 only, it requires a 64-bit kernel which excludes some early Core 2 Duo's.

Well, that is not good news.

Here's my issue exactly, maybe there is another solution besides a Windows VM.

Cisco VPN will not run in 64 bit mode on OSX. I didn't realize ML couldn't use the 3 + 2 when booting to boot into 32 bit mode. I've already upgraded and now I'm stuck. I cannot use the native Mac VPN for Cisco because the receiving side is not up to date and won't accept it. It has to come from Cisco VPN Client. Any other ideas besides loading a VM for Windows, which I do not want to do. Thanks.

You could revert to your previous OS.

Theoretically, I could. Do you know how I would do that? Is there a way just to revert without having to install from scratch and reinstall everything I have loaded?

ke715 wrote:

Theoretically, I could. Do you know how I would do that? Is there a way just to revert without having to install from scratch and reinstall everything I have loaded?

Restore it from the clone you made of your hard drive right before installing Mountain Lion.

I'm a fairly new Mac user, just a little over a year now. Long story is that I did not make a clone of the hard drive before the upgrade because I do not know how to do that. I had investigated when I first bought it because I previously used Acronis Image with Windows and I like the idea of a clone.

I had already tested the upgrade for a week or two on my Macbook Pro before loading it to my Air. I run Windows on my Pro through parallels and I only have to use Cisco VPN for one customer. It hasn't come up that I needed it on the Air until now. I'm going out of town and would really like to only take the Air, but may end up taking the Pro just for this purpose.

I will investigate creating a clone of my drives.

Thanks for your help.

Kim

Look into Carbon Copy Cloner or SuperDuper for cloning software. I prefer CCC because it will make a Recovery HD.

Good Luck

leroydouglas wrote:

Not only is it x64 only, it requires a 64-bit kernel which excludes some early Core 2 Duo's.

I'll bite... what C2D's are you contending are not 64-bit?

Marc Wilson wrote:

leroydouglas wrote:

Not only is it x64 only, it requires a 64-bit kernel which excludes some early Core 2 Duo's.

I'll bite... what C2D's are you contending are not 64-bit?

Core 2 Duo Macs with the capability of booting to a full 64-bit kernel however excluding some of the older graphics chips like the integrated Intel GMA950 and X3100.

Macs that do not to support OS X Mountain Lion

Older Macs and those with weaker GPU’s will likely be left behind:

• Anything with an Intel GMA 950 or x3100 integrated graphics card
• Anything with an ATI Radeon X1600
• MacBook models released prior to 2008
• Mac Mini released prior to 2007
• iMac models released prior to 2007
• Original MacBook Air

In other words there aren't any C2D's that aren't 64-bit.

Good to know that Intel's documentation is accurate.