Known unused sections of calibration files...
Posted: Tue Apr 27, 2021 12:43 pm
Kind of an oddball question, lol.. Someone was starting a discussion on another post and I believe the gist was they wanted to be able to choose the CVN of each segment and have it pass checks.. The Checksum isn't so important as that's not given with scan tool requests, it's the CVN that is checked.. I did a quick search but I didn't see it being discussed.. Kind of got me curious so I poked around a little.
With 2 bytes somewhere in the segment it appears I am able to make the CVN pretty much whatever I want it to be.. Problem is I don't know for sure the 2 bytes I chose are unused.. Yeah, at the end of each segment there's usually a lot of ff's that can probably be used, except for the last segment of the bin because that has 8 bytes that are used.
Any way to know for sure? This started with an E67 ecu but I could see this being attempted on E38's E92's, etc... The header of each segment has a bunch of info in it, but does anyone know for sure if there's 2 bytes not used for anything there? or am I pretty much guaranteed that if I go to the end of the segment and count back 8 bytes and use those 2?
With 2 bytes somewhere in the segment it appears I am able to make the CVN pretty much whatever I want it to be.. Problem is I don't know for sure the 2 bytes I chose are unused.. Yeah, at the end of each segment there's usually a lot of ff's that can probably be used, except for the last segment of the bin because that has 8 bytes that are used.
Any way to know for sure? This started with an E67 ecu but I could see this being attempted on E38's E92's, etc... The header of each segment has a bunch of info in it, but does anyone know for sure if there's 2 bytes not used for anything there? or am I pretty much guaranteed that if I go to the end of the segment and count back 8 bytes and use those 2?