For easy reference: How to mount a Chameleon EFI volume

I recently decided to use Carbon Copy Cloner to move the SnowFalcor partition (OS X 10.6.3) I've been using for the past few weeks, onto the fastest of my hard drives. However, that means changing the default boot partition in the com.apple.Boot.plist file on the hidden EFI partition of the drive I boot with. But it having been a good while since I've had to mess with this stuff (and that's a freaking wonderful thing, lemme tells ya :), I had forgotten how to do that. So, from Terminal:

sudo -s
mkdir /Volumes/EFI
mount_hfs /dev/diskXs1 /Volumes/EFI

Then either edit or create the following key-and-string pair:

<key>Default Partition</key>
<string>hd(x,y)</string>

Use the command diskutil list to see what your volumes' identifiers are, and replace x to be the disk number and 'y' to be the volume number (e.g., for a volume labeled disk0s1, x would be 0 and y would be 1).

Don't forget to unmount the EFI volume before rebooting, otherwise it can cause problems later on. To unmount, run this command in Terminal:

sudo umount /Volumes/EFI