Bread80Did someone mention bodge wires? This is a bodge switch - the bottom left one. I assumed the RP2040 had a bootsel switch, like a Pico. Instead it has a reset switch. This switch and a bit of wire is connecting the bootsel pin to a ground pin on the rear.
I was having trouble getting the RP2040s into Bootsel mode. It turns out I’d done a rubbish job soldering the Bootsel and reset button.
Not helped by me buying the wrong buttons - I bought recessed ones which need a pen (etc) to push. Holding test probes plus a pen at the same time required some ingenuity.
Reworked them now and working reliably under windows.