Issue flashing a new tcm

Working on an 09 duramax that had a bad A50 tcm. Got a new unit from gm and realized it was an A40 after opening the box. Now I know you can run the A40 in the trucks with no problem. The issue im having is giving it a calibration flash. I have an A40 read from and earlier LMM and am trying to flash it but when I do im getting a an error $0540: Incompatible operating system, OS mismatch between file: 25941751 and controller 24256580. I've flashed many new blank A50's in the past with no issues at all. Not to sure what I have to do with this A40. Any help would be appreciated

A40 is a PITA.

GM ONLY TOOLS for a OS CHANGE, if you attempt an OS Change there is a high likelihood it will brick, the A40 TIS Lookup is an absolute nightmare, it requires the TCM Part Number and Vehicle VIN Number and the correct OS and Segments for that exact combo.

Get the proper A50 TCM and forget about that A40

I am sorry if I am in the wrong area as this is my first post to the efilive forum. I am trying to read a 2009 LMM TCM with v2 but I am getting an error saying the tcm is locked. Can someone help me please?