Hi cseils,
Yes, it is possible to enable OData and use Code First entities.
Be sure to decorate your Code First entities with the IgnoreProperties and DataServiceKey attributes:
[IgnoreProperties(@"EntityAspect", @"AAAA_EntityAspectForSerialization")]
[DataServiceKey(@"MyEntityID")] // where MyEntityID is the entity's key
Also, you might want to implement System.Data.Services.IUpdatable to support OData updates.
Regards,
Silvio.