the font exploit loads phoenix, which then loads a Boot From Media bios and then loads evox.
i assume as soon as pheonix is run, the main default bios is shut off and a pre-programmed bios in pheonix is used until it gets the chance to boot the BFM one from the hard drive.
That is why when phonix loads on the new xbox's, the screen goes funny, because the bios its using is an old one, but then it boots the M7 or whatever from the hard drive and all is good.
Then EvoX loads.
So i reckon when a new phoenix is released, they will update whatever bios it uses initially, thus fixing the loadup screen.