Microsoft has rolled out yet another update to the Xbox 360 Fall 2011 Preview Dash, this time bringing it to version 2.0.14696.0. During the preview thus far, backups of MW3, for example, have been observed to flip states between working and not working — twice over. The same has been found with several other games. It's no surprise that many are wondering just WTF is going on.
Contrary to recent rumors, however, MS has not been reverting the dae.bin change/silent update. In actuality, following the silent update of the dae.bin on retail dash 13604, it was quickly determined that MS has been issuing a series of TitleUpdates for certain games (e.g. MW3) alongside the dash updates and dae.bin changes. These TUs appear to be testing the ability for Microsoft to enable/disable triggering of AP2.5 challenges against the disc via the multi-table dae.bin. This is accomplished by patching the default.xex executable with patch files (".xexp"s) in the TU which patch in or out the Disc ID within the xex header. When the Disc ID is present, and the game has an associated entry in the dae.bin tables, the AP2.5 challenges are triggered. Conversely, when the ID is missing, the system will not be able to find an associated entry in the dae.bin tables, and therefore no AP2.5 checks are performed. This accounts for the success of "TU trick" that people have been using to temporarily bypass the updated AP2.5 challenges (clearing the cache of existing/newer TUs and tricking the 360 into using an older TU that doesn't patch the Disc ID into the xex).
Being ranked at #1 for Xbox LIVE activity according to the latest charts, MW3 makes an ideal candidate for these types of tests by offering the largest possible test group. Based on this, Microsoft have shown that they now have two methods by which to control whether a game is AP2.5-active. A title may be AP2.5-activated either through the addition of associated entries in the dae.bin tables, and as it now stands, by way of TitleUpdates patching in or out the Disc ID.
Now, you may be asking yourself why MS would want to deactivate AP2.5 on a game. A team member suggested that this may be to allow MS a method for easily disabling AP2.5 for a particular game if it causes issues on retail consoles (this may coincide with the reports of retail copies failing AP2.5 challenges and showing "Disc Unsupported" errors). Purely speculating here, but testing of these TitleUpdates may also be a sign that Microsoft is preparing to issue AP2.5-enabling TUs for some of the more popular older XGD2 games beyond the original six affected (Assassin's Creed: Brotherhood, Call of Duty: Black Ops, Call of Duty: Modern Warfare 2, Fable III, Halo Reach, and Need for Speed: Hot Pursuit).
*UPDATE* [2011-11-23 11:37AM UTC]
As an added note in response to questions we've received, the usage of TitleUpdates in (de)activating AP2.5 in no way affects c4eva's "silver bullet" solution being implemented in iXtreme LT+ v3.0. C4eva noted in private earlier that with his solution, all current and future effort put into AP2.5 by MS is all for nothing.