Segment swapping

Playing with swapping an 12212156 OS from Auto to Manual, using the info i found here http://www.gearhead-efi.com/Fuel-Injection/showthread.php?3677-Segment-Swaps

(i commented there but figured it'd be better as it's own thread)

I believe i have successfully copied the Trans and Trans diagnostic sections from a matching OS (5.3/ manual calibration) but when i try to verify the checksums in EFI live before i reflash them, i get a failure on ENGINE and TRANS diagnostics. Attachment 14624

EFI says this may be just because it was edited outside of their software, but i want to be sure before i try to write the calibration and brick the pcm.... Any other ways to make sure it's cherry before i hit the button?

If you used a hex editor to swap segments then the checksums will be incorrect. If you take the modified file and swap the segments back, the checksum should again be correct. This twice modified file, when loaded in EFILive, should not show checksum failure. I think that would be a good test to confirm you are performing the operation correctly.