"Appendix A: Debugprobe" in the Getting Started PDF has a "Debug with a second Pico or Pico 2" section, which mentions debugprobe_on_pico.uf2 in a couple of places; but it doesn't clarify that this is the UF2 file for Pico 1, and Pico 2 needs debugprobe_on_pico2.uf2 (see https://github.com/raspberrypi/debugprobe/blob/master/README.md ).