you can get this working by editing a plist file:
open a terminalnew Terminal window
edit: /Library/Preferences/SystemConfiguration/com.apple.Boot.plist
/Library/Preferences/SystemConfiguration/com.apple.Boot.plist
Insert “mbasd=1″
mbasd=1
in the value<string></string>
value below the Kernel Flags<key>Kernel Flags</key>
. If the string is not empty to begin with (it normally is) or doesn't exist (sometimes happens), then use a space to separate the mbasd=1 from what’s already there or create the entry.
The original solution was from Lukas Zeller's blog here
A Gist is available on GitHub for this change also.