upyas wrote: Thu Jun 25, 2026 10:37 am
i get that, i am just trying to keep my tune out of the hands of a kid who thinks it is ok to copy and sell my tunes, he will not be able to make one himself to tune so he bought one of my ecus this is why i want to do it.
Back to the answer is No.
Whatever you do to the Eprom/Flash the stock ECU/PCM must be able to read it, so it must output the tune as per normal to the pins it normally would.
Whatever you implement on the ROM to protect it will be on the ROM protecting it and visible to anyone that can read said ROM to undo, or simply power it on and read it like the ECU does, extra stuff doing nothing useful.
Since the memory can be manually read, it will never be safe from someone actually reading it out.
But with enough time and reverse engineering, you could implement your own setup with a custom OS that verifies the ECU is running only in the car its designed for.
Personally, I would create a custom patch to either make a request for information from the BCM, or to lockout usage until it has compared and seen those security bytes being received from the BCM.
This would allow each vehicle to have a custom flash created thats specifically tailored to that car only, meaning a 'copy' would not work in the next car.
With that said, its probably thousands of hours of work to reverse engineer the target OS, create the patch and test over multiple different OS's.
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I wouldn't even go that far. I'd change the key, and move mode 36 read to another non-standard number and patch the flash tool to send the custom key and oseplugin to read on that chosen non-standard ID. It's all possible but its not built for it and it's hacky and it takes a certain amount of skills. Without enough time and skills you'd probably brick PCMs trying to make it, and like everyone says a skilled attacker could get around it. But I assume the aim is to just stop it from being readable with oseflash tool out of the box by a n00b. Except now I've written this idea here, that's the first thing they'd look for.
yeah i just want to prevent this kid from doing clones on them, not trying to protect it from anyone who knows what they are doing because they can just make it themself
upyas wrote: Fri Jun 26, 2026 1:58 pm
yeah i just want to prevent this kid from doing clones on them, not trying to protect it from anyone who knows what they are doing because they can just make it themself
Simple solution, don't sell the ecu/pcm's to the kid.
Problem solved.