I think you are asking about the stealth media patch. This is a combination of the PFI patch and DMI patch. Sorry I can't get technical but this just makes you more safe from future checks MS may come out with.
Stealth media is different from stealth firmware patch.
What this basically does, is protect us somewhat from future checks Microsoft may implement against the firmware modification in the future. If Microsoft release an update for our 360's to check if you have modified firmware, the drive will report it back as unmodified (even though it is).
Edited by wassabi, 21 January 2007 - 12:58 AM.