Hello, @VaneB
1. I've been successful on the same board before. After that, it's the same error regardless of other boards.
2. The picture below is my pin picture and connection picture. I selected J7-2 to connect Port B-7. J7-4 to connect Port B-9, J7-6 to connect Port B-13, J7-8 to connect Port B-5, and J7-10 to connect Port B-15. In addition, I also connected the VCC and GND of J7 to Port B.When I do not connect VCC to GND, one of the U-multilink lights will not be lit. I don't have the document you asked me to refer to. If possible, I hope you can send me a copy for my study.







3. This is the waveform of my RESET pin. I should note that this waveform is only available when I do not connect VCC to GND. When I connected VCC and GND to Port B, the Reset waveform disappeared.

best regard,
zenging