So TP5 automatically calculates checksum. As far as I can tell, when I went with TP5, my emulating/chip burning is wrought with "random" problems, at least with the '165.

Sometimes, the CEL flashes as it should, but the truck won't start. Sometimes the CEL doesn't flash, but illuminates when the key is in "run", and the CEL shuts off once the truck starts, but appears to be running off the memcal. Pulling the PROM normally resolves the issues, and I can go drive it. Sometimes while emulating making a change will kill the motor.

Code 51 is pretty much constant (even without a CEL), but I haven't checked if it's still there after removing the PROM or APU1 cable. Before I had just turned the truck off, uploaded the bin a couple more times and that would "work".

In TP4, I had disabled the checksum, and that was that. I don't recall any issues like this with that version.

In this XDF, mask ID is solely numeric. I can't select AA. If I set Mask ID to 170, that SHOULD disable checksum. Correct?