I got my boards back from ChipGeek and got the first one assembled. It does a very slow ramp up on the volts but as soon as it hits 1.1v it crashes.
I've some which have >= 25 engines. I do not active cooling strong the psr chip area so the temperature will limit the voltage below 1.13 V. Mine mostly crash above but not below. So mostly they are stable hashing now.
And yes, we are need a voltage limit for boards above 25 Engines. Maybe we can have a small formula which will calculate the endvoltage maybe if engines > 24 then 1.16 V - (noOfEngines-24) * 0.02 V elseif <=24 1.16 V else 1.1 V or so ;-)
Another way is to store the voltage at the crash, decrease it a little bit and use this as a new upper limit at next time. In this case we need only one fw for all boards.
Cheers...