DHT22 running @ 8MHZ

Working SW is always good news.

however if I look at the solution it implies that somewhere the timing has changed by a factor 2
(side effect of going from 16MHz to 8MHz)

Can you confirm this effect also in the other DHT libs? Adafruit & mine?

update:
in my DHT lib these lines

        if ((micros() - t) > 40) // should be 20 ?  can you try?
        { 
            bits[idx] |= mask;
        }