With [Aaron Christophel]’s method, you can find the SWD interface on a PCB within a few minutes’ time. All you need is two needles, a known-to-be-ground connection, an SWD dongle of some kind ...
[Dima] wanted to make his boards easier to flash, and developed a PCB footprint and flashing tool ... Having trouble finding the SWD points on an existing device? Try this method.