My friend has HPT and we tried pulling the tune on my dually to get a look at the 4lo stuff. Hunting for a spot with the camper, I actually have a use for 4lo but with the COS the way it is I'd have to wind it out to get the thing to shift out of 1st. Seeing how HPT can alter this stuff, I'm wanting to get this fixed as I know another guy with their version of a stream license who will hook me up. We were unable to get my tune pulled, it always failed at the halfway point. There was something it definitely didn't like. We then proceeded to warm over the stock tune on said friend's 2005 GMC 2500HD 6.0/4L80 and I can say with absolute certainty that those trucks are far more finicky than mine when it comes to reading and flashing. That said, since updating my software/firmware my EFILive has been an absolute peach with those era trucks. If I were to get HPT to read, would a flash mess up my COS stuff? Would I need to full flash un-COS, alter that stuff with a cal only flash, re-COS, then dump my current cal only tune back on to make it work? I was gonna monkey with the throttle lift TCC unlock stuff inherent to the 4L80 as well.