6.4l and tuner problem

[chif39]

I have a buddy that has a 2010 ford f350 with a 6.4l powerstroke he had a bully dog tuner on it. He had to takein for some warranty work, so he pulled the tuner off before he took it in to the dealership. When he got it back he tried to put the tuner back on it and he told me that the dealership put some kind of chip in it that has got the ecm locked so he can't put the tuner back on it. Has everyone heard of this or had it happen? If so does anybody know of a way to unlock it so the tuner can be put back on? He really hates the fuel mileage he gets right now.