Microsoft has popped the Ninja Gaiden 2 Mission pack back on Xbox Live, but there are still freezing problems that need "a little more time to figure out".
However, the Achievement hiccup has been solved, and anyone yet to unlock any of the 10 new rewards should be "good to go", according to Microsoft's Gamerscore blog.
Those who have already run into problems with the Achievements are advised to clear the console cache or recover their Gamertag.
To clear your console cache, go to the system blade in the Xbox 360 dashboard and select "memory". On the HD symbol press these buttons in sequence: X, X, left bumper, right bumper, X, X.
Once complete, a message will pop up asking if you want to perform maintenance on your storage devices. Yes you do. But remember: by clearing your cache you will need to download any software updates again.
The Ninja Gaiden 2 Mission Pack costs 800 Microsoft Points (GBP 6.80 / EUR 9.60) and adds 10 new Achievements to the game.