I purchased a duo expansion board, and am not sure how to enable the ARM core. Per the docs, in order to use the ARM core you have to “short physical pin 35 (Boot-Switch) and GND”, however all the pins get inserted to the expansion board and I’m not sure if it’s possible to connect two pins after they’re inserted. Any suggestions?
You can still short the pins anyway: solder a jumper wire or something there.
And you will need to use a different firmware image, btw.
Moreover, here’s shown how you short the boot select pin to ground, and basically it doesn’t matter whether you place a removable jumper, or solder a wire onto the Duo board, or solder it to the expansion board — the result will be the same.