I noticed yours is running very cool.
I'm just using the small fan that came with the case. I have on my long To Do list to use some larger fans to blow across all the Kiwis. I have a plan to build an enclosure to house all of them to clean things up a bit.
It seems to work just fine other than those modes that it won't decode. Interesting though if you output the tones to a secondary decoding application, it works just fine.
Must be a problem porting those extensions over to RPi.
Is the mod for high frequency cutting the 0-30mhz portion lo-pass filter on the secondary port out the circuit? So disable the 0-30mhz port? or something else?
That was all I did. Fortunately, I don't drink coffee so my hand was steady enough to do that mod. Those parts are small and very close together.