con 2> =set_focus(1)
I'm sure you camera cannot focus at 1mm. This *may* focus at the closest possible distance, but I wouldn't count on it.
I don't think my camera supports manual focus, should it then support set_mf?
It works on many cameras that do not have native MF, but CHDK is a hack so ¯\_(ツ)_/¯
Looking at the port, it's using the "PressSw1AndMF" which IIRC may have been a false positive in the test script because the camera can override in AF, it looks like it works even though the levent has no effect.
From the log you posted, it looks the the PT_MFOn / PT_MFOff eventprocs might work (though could be false positive as well?). Attached is a test build using this method.
If set_mf is working with this build, you should be able to see the focus change on the camera screen (or PTP live view) when you do something like
set_mf(1)
set_focus(50)
set_focus(10000)