The recent silent DAE update stopped all AP2.5 / XGD3 backups from booting. Until a solid solution is released, here is a simple workaround
Thanks to Dattran over at XPGamesaves.com for discovering this simple work around.
For this example we are going to use MW3.
1. Get a USB flash drive, At least 1GB in size and format it (FAT)
2. Insert into Xbox and goto memory devices. Select USB and configure it as a storage device.
3. Download the this MW3 Title Update
Click here.
4. Download Horizon
Click here.
5. Select Tools > Device Explorer
6. Plug in USB device to PC
7. Device will be detected. Select Inject File
8. Load the the MW3 TU that you downloaded.
9. Connect the USB stick to your Xbox. Restart and boot your MW3 backup.
Notes: You may have to delete the system cache after every time you do a fresh boot of the game. But hey, it works. You can get other title updates from here:
http://www.xbuc.net Nothing is ever live safe. It may work, it may not. I’m not your mom make your own choice.
Please report if you have any success / links to TU’s / better methods.