david_prentice:
D10 does not seem to blink on the EVERY.
According to the variant file:
Arduino pin 10 is PB1. I looked at the code in that file and it seems correct for PB1. So my question is whether Arduino pin 10 on your Nano Every is actually connected to PB1 on the ATmega4809. I don't have an Every so I can't check this, but it should be easy to do with a multimeter set to continuity check mode. PB1 is physical pin 5 on the ATmega4809.