Long story short, I've installed a new TCM in my 09 LMM GMC. I used EFI Live to read my original TCM and full flashed that to the new TCM. Now, I'm getting a constant U0101 code and intermittently cannot communicate with the TCM via the tune tool. I've re-flashed with my factory tune file, the original file from the replacement TCM, and a factory tune file from another truck with the same OS as mine from a friend of mine. No joy.

Anyone have any ideas?