GMPP E67 LS2 Crate checksum issues

I read the stock file out and it had all checksums disabled. I ran the checksum fix and reflashed. The car runs fine but does not appear to be accepting any changes like idle speed etc... I read the file out again and noticed that the OS checksum still says it's disabled. The rest of the checksums are ok after the first calibration reflash.

I'm assuming I need to do a full reflash with the updated checksum to fix this? I've never ran into this before and I just want to make sure I'm not going to brick this E67 with a full reflash. It still runs fine as of right now with a calibration only flash. I got no errors during the flash.

Yes, you need to full flash the ECM to apply the OS checksum fix.
It's probably not necessary for you to do that at this stage though. The checksums must be fixed prior to flashing because EFILive's reflash process will not allow the ECM to reboot to normal running mode unless the checksums are 100% correct. As you have already applied the checksum fix to the calibrations area that is fine for continuing to do cal only flashes.

He'd logged a helpdesk ticket also, and I said basically the same thing :)

Thanks guys, that is what I was thinking but I wanted some input before I did the full reflash.