i got a mate with a mk6 1.8si who stupidly fitted a superchip to his car when it didnt match his ECU, after fitting it he took it for a run and it started playing up, lights flashing and stuff.

he took the chip out and disconnected battery and reconnected but now the car dont idle right or when cold from first start it will keep dropping the revs to about 300.

has he damaged the ecu? is there anything he can do?

any help will be much appreciated so i can tell him his a muppet..lol