To sum up the software and hardware situation, 2B it would seem is possibly nearly as per specification, 3i is meant to do the same as 2B on a different hardware platform. Having an aircraft that has flown with 3I does not mean it is tested, implicitly it cannot be signed off till 2B is fully signed off, as it is meant to mimick it. 3I was meant to be a stepping stone to 3F that all users were planned initially to declare IOC with.
Neither version is ready for fleet release.