New Post: EF 6 and async for .NET 4.0 ?

Yes, that is correct. What is missing is the async APIs in the ADO.NET base classes under System.Data.Common. Microsoft.Bcl.Async provides extension methods for SqlClient only, and only for the async methods that were already exposed using the old async pattern in .NET 4.0. Those are a subset of the async methods exposed in .NET 4.5 which the async implementation of EF depends on.