Or does someone have a good clean stock file I can use for this truck. Tried finding one online, but with tunefiledepot down, i'm not having much luck
The OS appears to be very early for that VIN number.
12593058 is the latest updated OS for it. You can always verify here with the vin number https://tis2web.service.gm.com/tis2web
I only have the early one you show but from a 2WD.
I have the later one from a 4WD.
Re-read it and see if the checksum is good the second time. If so then discard the first read because it must have been corrupted while transferring from the ECM to the PC.
If it always gives the same failed checksum value then it is possible that the checksum has always been bad in the ECM but that someone has disabled the checksum validation in the ECM. In that case I recommend starting with a different, known good file. Then copying whatever calibration values you want/need from the bad file to the good file.
Regardless of how/why the checksum is bad you should never flash a file with a bad checksum into a controller. You should never "correct" the checksum unless you know for absolute certainty that the data in the file is not corrupt. Usually the only time that is true is when experienced tuners are modifying binary images using a hex editor and are simply using EFILive to correct the checksums after they have modified the data.
Regards
Paul
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