So when I change the VIN (either in v.75 or Tune Tool Properties) the original VIN is still showing in the TCM when I perform an F2: Read. I have done a Cal Flash, Full Flash and a Flash in V2. It doesn't matter. As soon as I pull the calibration the original VIN shows up again in the TCM. It even shows the original VIN in the V.5 "Show PCM Info" pop up.
Software and Firmware are up to date. Any ideas? Is this some new GM witchcraft to keep the original VIN locked in the TCM?