Did not read the entire thread but here hare my observations from today (using the March 0326 FW and the latest build) :
- TCM flashing works
- Logging in passthrough works, but selecting the controller was a little odd, had to select with ignition on!
- Clearing DTCs works for all controllers from PC but I was unable to clear B1025 and a Cxxxx DTC standalone.
- BBL did not work, got the message that PID TP was unknown.


Tests were all performed on my 05 LLY Duramax truck.