MAC OSX boot 64 bit kernel mode default

1. power on your MAC and push keys 4 & 6 on your keyboard until inter your desktop.

2. open the terminal 

     # uname -a

    if it displays ........X86_64 , and you are in the 64 bit kernel.

3. sudo a super user to do these command & you need to type your 

    root Password after the sudo command 

     # sudo nvram boot-args="arch=x86_64"

     # cd /Library/Preferences/SystemConfiguration/

     # sudo vim com.apple.Boot.plist

<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>Kernel Flags</key>
<string>arch=x86_64</string>
</dict>
</plist>

Edit this file arch=x86_64, and it is original srv=1 

or you can copy & paste on it. 

4. restart your mac without any key pressing on your keyboard and open ternal

     

     # uname -a

    

if it displays ........X86_64 , and you are in the 64 bit kernel. 

The boot kerkel is 64 bit now.