Xantia II Hydractive Circuit Diagrams

[AbangCorp]

i learnt electronics & electric in university

if we cannot program it, then we can at least read the program (waa, sort of citroen engineer at that time)

i did it before for my microp and microu
just need to make sure what technology chip they install in
how many pin (i think at that time it is still this mature chip technology)

after reading, alter, buy the same chip & burn
you got a whole new setup

[xantia_v6]

The snag with that approach is that you either need to dissect a new ECU that has never been programmed to get the image, or reverse engineer the software to deduce what the unprogrammed image should be.

In some cases neither of these is practical because some or all parameters (or a security key) are stored in a secure area on the processor chip itself, and cannot be read via the pins on the device.

[addo]

It would be nice, though, to have a means of re-programming them.

Would a design that old, really be so impenetrable?

[xantia_v6]

Would a design that old, really be so impenetrable?

I was designing microprocessor systems in the late 1980s that had one-time-programmable security keys on the processor chip (and that was the 68HC11 which at the time was the most widely used chip for fuel injection ECUs).

It is more likely that there isn't any physical security on the Hydroactive ECU, but a lot of security-by-obscurity, which means many hours of digging through disassembled machine code to figure out how the programming works.

[AbangCorp]

you know, i am always not really sure what i did back then
but sure i miss out some important tedious thing, the processes in between