Debug Probe fails on RP2040 revision B1

[Gerhard-Vienna]

When my homemade debugger stopped working with 'Picoprobe', I loaded the 'debugprobe' firmware. However, the debugger fails with
Error: Could not connect multidrop rp2040.dap0

I got hold of an original 'debugprobe' and as it worked fine, I assumed it was the pico I was using. So I tried it with different picos, but the result was always negative.

The solution then lay in the output of 'picotoo info -a'.

The picos I used were all revision B1, whereas the original pico probe was revision B2.
Replacing the pico in my homemade debugger with a recently purchased one (B2) solved the problem.

Details:

• OS: Linux, Debian 12

• openocd -v
  Open On-Chip Debugger 0.12.0+dev-gebec9504d (2024-11-25-20:09)
  Downloaded from https://github.com/raspberrypi/openocd.git

• debugprobe:
  sdk version: 2.1.0
  pico_board: pico
  boot2_name: boot2_w25q080
  build date: 20 Dec 2024
  Build attributes: Release
  Downloaded from https://github.com/raspberrypi/debugprobe.git

I'm not sure if the lack of support for older picos is intentional or a bug. In any case, a note in the documentation (Getting Started...) would be appropriate!

[lurch]

I can't think of any obvious reason why it would work on an RP2040B2 but not on a RP2040B1, so pinging @P33M to have a look at this after the Christmas & New Year holidays.