tunerpro checksum issue

[pmcquay]

I'm not sure if here or tunerpro forums is the best place for this, but since the person who wrote the xdf is here, I chose here first.

I've successfully read the contents of my pcm, 12212156 os. I then installed TunerPRO, and loaded the attached XDF and the attached BIN, attempted to change the differential ratio, and then save, and got the following error: "Error - one or more checksums could not be updated. Check checksum addressing, etc, for validity."

I did some looking around, and it seems like I might need a checksum plugin? (or not, one of the places I saw talked about only needing that if I changed things outside of calibration?) so I grabbed the one referenced in TunerPROs downloads page and put it in the plugins directory. TunerPRO did not list it in help->plugins. Not sure what has gone wrong there.

Do I need a plugin? Is this the right XDF? Am I insane?

[antus]

Without looking at that exactly at the xdf, yes a lot of XDFs do need the right checksum plugin to calculate the operating system checksum. Unless you applied a code patch you dont need to update this checksum though. Since you only changed the diff ratio, the checksum error can be ignored. I have checked your bin, all checksums are correct.

[pmcquay]

Why would TunerPRO give me that error then? That bin is a virgin copy so it should have correct checksums.

[antus]

Because tunerpro cant do a non-contiguous checksum out of the box (only a single start to end address of type), and the OS checksum is not contiguous. So the plugins take the start address and the end address, and look at the data and skip over the bits that are not part of the checksum. The checksum means the OS checksum can be calculated for OS patches when its setup right with the right plugin installed, but without the right plugin you get the error when it trys to calculate and update all checksums on save. Its a bit of an unfortunate situation how its all evolved. If everyone was on the same page to begin with I think the plugins would be used by less XDFs, or if tunerpro was developed further so it could do 2's compliment for multiple ranges for a single sum, or if people didnt set them up like this when they dont need to then lock the XDFs and disappear we wouldnt have this now.

[pmcquay]

Ahh, okay, so if I understand it right, that error is saying that it cant calculate the os checksum, but all of the others have been updated? Does PCM Hammer double check that? I think I read somewhere that it does.

How do I know what plugin I should have for the os checksum? Is that specified somewhere in the XDF?

[antus]

Yes pcmhammer checks the checksums before it flashes. Unfortunately you cant see whats wrong with the XDF if its locked. If its not locked you can look in XDF/View edit XDF header info/Checksum Tab then go through the checksums and see which ones need a plugin. If its only the operating system you can delete that checksum and you know your OK so long as your not patching the OS.

To know which plugin is harder, and there is no good answer. The checksum plugins have a GUID (globally unique identifier) internally which looks like xxxxxx-xxxxxx-xxxxxx-xxxxx-xxxxx with letters and numbers (thats not literally the format, just from the top of my head). Internally the XDF has this number. But you have to know what plugins are out there and the xdf has to be unlocked to figure it out. Best case is you get a zip with the xdf and it also contains the matching checksum plugin, if it needs one. XDFs where you need to find the plugin from somewhere else are probably best thrown in the bin to clean up what files are being handed around.

[pmcquay]

Do you have such a zip file laying around for this OS? I did do some looking but there doesnt appear to be one comprehensive place to get these things.

[antus]

I think its using this plugin, of mine. At least it loads ok on my pc and this is the only one I currently have installed.

[pmcquay]

I got the xdf im using from here: viewtopic.php?t=51&start=10 is this fine or would you recommend something else?

Another thought I had, since TunerPRO checksum calculation is somewhat fragmented, why not have PCM Hammer calculate and insert the correct checksums at write time? Then the xdfs wouldnt have to contain any checksum information.

[antus]

Ive added the plugin there in that thread, so hopefully that helps. I dont think pcm hammer should update plugins, because they are there so that any damage to the file can be identified as a safety feature. If it updated the checksums, it would be too easy for people to flash damaged files in to their pcms and create bricks.