Flashing over locked HP tune?

[machinist09]

Is it possible to do a complete flash over a locked HP tune? I have an acquaintance whose son blew his motor up, and a condition of dad helping him get a new motor was that he puts the factory tune back on, since they are 90% sure that the HP tune is what caused the problems. They took it to GM, and their tool can't access anything. Truck is an '05 Avalanche with a 5.3L. I can find a factory tune to flash, just need to be able to flash it back on. If so, does transmission shift pattern change based on rear gearing, or would only speedo have to be rercalibrated? I don't know LS systems at all. Thanks guys.

[GMPX]

If the tune (actually the PCM) is locked then no you can't just flash over it, you need to have the PCM unlocked first which is why GM's systems couldn't flash it either. Once that is done then you would be able to flash over any program you need.