Adding more info, sort of a parallel thread since kw1281test doesn't help those of us having petrol engines but probably good to have referenced since search engines got me here originally and might be useful for future owners.
I was eventually able to get the tools from Nefmoto. Be persistent, the forum is tempermental.
I was able to use "me7_95040_v1.31" get the EEPROM dumps via the the diagnostic port but the tool failed to write to the EEPROM, which is expected. To write you need to get the ECU to accept new values and that requires the ECU being in boot mode. Normally this is done by shorting a pin on the microprocessor to ground briefly when you power up the ECU.
Supposedly it can be done via OBDII port but it looked to me only specific types of interfaces would work and the KKL 409.1 red cable I have is not one of them. I didn't look into great detail but it seems some of them can pull down a pin on the port the ECU expects to allow writing. To do this it seems they bit bang one of the chip select lines and either they've only figured this out for the Prolific based intefaces or the FTDI ones (like I have) just can't do it. Like I say, I figured the lack of clear detail didn't give me confidence to I abandoned this approach.
Alternatively bench harness or opening them are relatively well documented and I felt this was a safer (to me) approach.
I considered building a bench setup and try to do it via the OBDII path. I'd have to pull the ECU and still take the lid off anyway, so I found it easier to just de-solder the EEPROM and do it manually.
Ultimately the VW-specific tool I needed was "eepromtool_04" to do what I needed to do. To do the actual firmware read/write I used an Xgecu T48 PROM/Flash tool.
I have to say thanks to you for clues on those ME7.5 tools (huge lifesaver) and to all the hackers who figured this out for us. Again,
@gmenounos, even though kw1281test wasn't needed having it originally and to poke around immobilizer and ECU has be invaluable.
