in tuner pros default xdf file there is a checksum calculator plug in. works on default xdf, will not work on custom xdf. so need xdf that has a working plugin for checksum. anyway. i posted in checksum update category, to see if anyone is nice enough to help until i can get winols full version. posted ori. and mod. not looking for a handout, just new to this stuff and trying get all the information i can on what works and what doesn't by some seasoned vets like yourself.
XDF all by itself simply does not have checksum checking or update capability. Checksum calculation is a function seperate from XDF (although it is handled through the XDF header set-up). No plugin, no checksum update. Simple as that.
See
http://www.nefariousmotorsports.com/wiki/index.php/Getting_Started and especially:
http://www.nefariousmotorsports.com/wiki/index.php/ChecksumsMaybe not an absolute, but I dare say that if you have the correct plugin and an XDF from the same family (7.1, 7.1.1, 7.5) even if it is not the "correct" XDF the checksum would calculate correctly (using MTX anyway).