看看这样行不行?我自己不用mac,所以没试过
1)http://refit.sourceforge.net/tripleboot/
partition magic主要是对付windows partition and file system的,不知道对hfs支持怎样?你可以试试gparted,a livecd.
2)Click the Apple menu and choose About this Mac, then click the More Info button. When the app appears have a look in the USB section and see if the device is being recognized.