The Inmarsat packets from the A/C contained an identifier code which has been compared to a MAC address. The identity of these packets as being from MH370 has been positivitly confirmed.
As for the radar: the Vietnamese state that they saw it turn around (circa 1:22) Thai radar picked up what could only be the same target approching Kota Bharu at 1:28 and the Malaysians picked up what can only be the same track shortly after that.
There is no doubt that this was MH370.