Ok guys, having a weird issue, but I think its related to the actual TCM, not a file. The customer dropped this truck off (2014 Chevy 5.3 E92/T43. He said he just got the trans completely rebuilt by someone and obviously they replaced the TCM, which I don't know why. Unless there was something going on with the original one. On the bottom of the trans he has written in black marker "MUST BE PROGRAMMED". First he took the truck to the local dealer. The dealer said they could not flash it due to the fact they couldn't communicate with the TCM.
When I received the truck and connected to it I couldn't see the T43 icon/picture pop up (V8) but could read the file in it, which is corrupt, so obviously not a "new/reman" TCM or someone has been screwing with it) and I was also able to license the TCM. The file that come out of it was corrupt with bad checksums. Corrupt file OS is 24270599. I went to TIS2 and verified what it originally come with, which was correct...24270599. I had a good read from a 2015 Chevy truck with the same OS. I flashed that file in and at the end I get the $06FF Checksum Failure error. Being a good file will not flash into here is it possible that the TCM is damaged? Or can the file be "fixed" somehow? I have attached both files. The one I read out and the known good one I tried to flash back in.