I don't have it anymore.
But from the top of my head, you need two files and both should have the mac address in the name of it.
These files should be in the same folder as the normal phone files on the controller.
You should also be sure that the phones get the tftp server address by dhcp.
I believe that mitel also has a document about this somewhere.
BAZINGA!
I'm not insane, my mother had me tested!