whether this is useful info or not i am not sure but here is my recent experience playing around with flashing another 360 i thought id check out for my self what this kiosk disc returns with the update/flash etc
so i have a standard un touched core 360:
-flashed it with xtreme.bin (i do not have any 360 backups working as of yet (too lazy to backup my own and its hard to get working SS files for australian games

). i noticed my ORIGINALS weren't even loading (they said 'please put this disc into an xbox360 console' ie. the video only was loading)
i read somewhere that u require the xtreme_PROPER.bin file, so i reflashed with this and originals work fine now (assumed the flash is perfect now)
i THEN popped in the kiosk disc and off it went, loaded played fine (burned on a dvd-r a couple months ago with my pioneer 110d and standard firmware)
i then inserted tomb raider original as i knew this had the update, let it update, turned console off then put in the kiosk disc which now fails to load (plain dirty disc error)
NOW..
the funny thing i have noticed is i had a game i tried to burn from a downloaded iso + ss file from the net which has not loaded although BEFORE i updated with the tomb raider disc i was getting and error 'this game might not be of your region, clean it, reboot console'..... NOW the same disc (after the update) gives me the same error as the kiosk disc 'dirty disc', but nothing about the region, and the burned disc was PAL i can assure you that... any ideas why? perhaps there is something other than the kiosk disc not being signed ie. a backdoor before the update is applied in the 360s core security? i am not wise enough to know but hopefulluy if there is the right person is reading this, or someone can enlighten me as to why the error msg has changed?