Preliminary Checksum Correction Tool:
https://dl.dropbox.com/s/ym8amldnz79...nTool.exe?dl=1
Not pretty, but it works (at least in my experience, let me know if you run into any issues).
Pretty simple to use. Point to an MSS54/HP file. If the checksums are correct, no changes will be made. If they're incorrect, the utility will correct them and backup the original file to originalfile.BAK
Requires .NET 3.5
Next step is to allow the addition of Shiftlights and/or sport memory via checkboxes. I'll do that later.