That's a good bit of info - thanks!
I tried with a 8.2k ohm and a trusty 120 ohm resistor from my canbus kit and no joy. I see one of the first posts in this very thread gave similar results on a VAG controller, so this must be the same issue.
I'll get more in-depth with the trials then, and will trace the CPU pins more and try different resistors. It's interesting as that document gives a different method for hitting boot mode than is conventional on here, (a switched 8k resistor), so need need to release it. The controller with 120r and also 8.2k r never booted in 10 secs with it held to ground on POL4. For the hell of it I also tried pin 24 on the flash as mentioned. This pin has continuity with POL4 as normal.
I'll take some pics during my next tests and an electronics wizard might spot something. It's gotta work if we get the recipe right.
The CPU is C167.
I slightly questing the kline pin as well but I know nothing of kline (lots of CANBUS). It generates a lot of weird serial traffic on boot and goes nuts when I poke it via Volvo CAN diag commands. I captured it roughly with putty and have attached it, it makes no sense at all to me.
do you know which version of the processor is in there?
also i saw this "The pulldown must
be strong enough to force the voltage at the P0L.4 pin during reset below the upper VIH limit of
0.2VCC + 0.9V. On the other hand, it must be weak enough to allow the P0L.4 output to drive a high
level after reset."
recommend's 8K resistor
http://alt.ife.tugraz.at/datashts/Siemens/ap160701.pdfthis may be an issue
"Note that the port pins P0L.2, P0L.3 and P0L.5 must be at high level, and stable during and at the
end of reset otherwise the BSL routine is not started. The state at the EA input pin has to be stable
during and at the end of reset, too, to avoid unexpected effects."