1997 F-Body ECM

[steveo]

One thing that is still missing in obd-1 pcm hacking is a bin descrambler from raw bin to usable bin.

i tried a few permutations of address lines but never got anywhere. i'd love to make a tool for that if anyone ever figures it out.

[Terminal_Crazy]

i tried a few permutations of address lines but never got anywhere. i'd love to make a tool for that if anyone ever figures it out.

I tried a little looking at the $EE Images.
I'd presumed the DATA lines were scrambled.
I hadn't considered the ADDRESS lines.

Would other .bin files generally have a constant phrase in the such as the © DE Corp in the $EE... although you'd probably know some findable data sequence.


Mitch

[Tom H]

i tried a few permutations of address lines but never got anywhere. i'd love to make a tool for that if anyone ever figures it out.

One project I worked on, we did with scrambled address and data lines. This was not done to obscure the binary but rather to ease the layout of the PCB. Specifically, there was a problem where a bunch of data lines needed to cross and it would have required an increase in layer count of the PCB to accomplish. (that or blind and buried VIAs) Back in the day, this was not good tech to use where vibration and heat cycles were a factor. It also CO$T bigtime due to scrap costs where it went wrong.

Writing a translator for data lines and address lines is trivial. Knowing which are swapped is the difficult part. The easy way to do this is with an ohm meter (with "beep") to determine how the traces are swapped. Armed with this a conversion can be written in a few hours. One will need only a mapping of which data&address on the processor connects to which on the FLASH. If bank switching is involved, that also needs to be mapped. On my PCM, a simple NAND gate is used. Which address line is connected to that gate is also needed.

If anyone wants this done, pm me with details of the swaps and I will write a console app to convert.
-Tom