If you want to play Xbox Live or you just want things back to factory settings, you will need to restore the Microsoft dashboard by selecting the "Restore Dashboard" saved game under the Campaign menu in MechAssault.

Since Microsoft knows of the MechAssault exploit, it has attempted to patch Xbox consoles as they connect to the Xbox Live network. So if you restore your Xbox to the original factory settings to connect to Xbox Live, you won't be able to easily reinstall the softmod because you will have a patched console. Before connecting to Xbox Live back-up your console's Microsoft dashboard. You will need to restore this pre-patched version before ever attempting the softmod again.

If your Xbox goes through a router, you can prevent Xbox Live connections by blocking both TCP and UDP on port 3074. Otherwise, do not select Xbox Live features or disconnect your console from the internet when unsure if a game will connect you.