32 bit mode

Discussion in 'OS X Mountain Lion (10.8)' started by tbluhp, Feb 18, 2012.

  1. tbluhp macrumors 6502a

    Sep 6, 2006
    I am trying pressing number 2 and 3 during boot and I am unable to get into 32 bit mode?

    macbook 2010 2ghz
  2. pdjudd macrumors 601

    Jun 19, 2007
    Plymouth, MN
    i *believe* OSX ML is 64 bit only - I don’t think there is a 32 bit Kernel.
  3. nostylluan macrumors member

    Feb 10, 2012
    there is no 32bit, that is why a lot of legacy comps can't run mountain lion.
  4. skaro macrumors newbie


    Oct 7, 2004
    You can still boot into a 32-bit kernel, but you need to modify boot.plist as holding 3 and 2 no longer seems to work. Just add arch=i386 in to boot.plist and reboot.

    I assume this will go in future builds but it works for now. One thing to note, it seems you can't access file shares in 32-bit mode for some reason.
  5. Ke5 macrumors newbie

    Jun 18, 2012
    Skaro - could you provide exact instructions on how to add arch=i386?

    Thanks in advance. I realize this thread is old, but I can't find this information anywhere else.
  6. skaro macrumors newbie


    Oct 7, 2004

    You need to edit /Library/Preferences/SystemConfiguration/com.apple.Boot.plist. You need to amend the Kernel Flags entry to look like this:-

    <key>Kernel Flags</key>

    If it doesn't exist just add it and then reboot.

    I have no idea whether this works in the release version of Mountain Lion but good luck :)

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