Retails Gears of War 3 can't boot on formerly flashed consol

[petrieslastword]

My friend and I both went and bought retail copies of GoW3, and have been trying to get them working on our modded 360 consoles. Google told me we would need to manually apply a system update, but I tried downloading that from Xbox.com and can't get it to load (I assume because I'm already up-to-date. The game simply displayed an E66 error. I flashed the console back to stock, and it makes it seem like the game will boot, but the disk image never shows up and when I hit play game, I am disconnected from live, the system hangs, then am booted back to the dash. Is there something I can do to get this working?

[petrieslastword]

Update:

Did the exact same things with his Xbox, and it boots the game just fine. He is playing now. Same things on my Xbox and the game won't boot and brings me back to the dash.

[sas67]

E66: DVD Drive Error: DVD model, or version does not match that of the version expected by the dashboard. OR the firmware version on the drive is older then the firmware version expected by the dashboard. Make sure the DVD drive is of the same version originally included with the console and that it is using either the original firmware included with the console or newer.