It isn't the ECU which is providing the Mclaren's an advantage. It's tyres which are proving to be a disadvantage for the scarlet team.
In a recent interview, we come to know that Ferrari chassis degrades the tyre lesser as compared to the Mclarens. Hence the Ferrari takes longer to warm up their tyres than the Mclaren and in the rain the Ferrari's find it very dificut to warm up their tyres. That's the reason why Kimi's tyres weren't changed in the first pitstop in Britian last time round. But Kimi's tyres had gone bald and hence he was struggling. For Massa I have no comments.

Racing cars are neither beautiful nor ugly, they are beautiful only when you win races.