Problems with DFU upload on PyCom Wipy

I have been looking at a SCADA/IoT platform to build my work around, and after a fair amount of research settled on the Pycom ecosystem. they are well built, available in a variety of form factors and feature sets. however I am having issues with the DFU firmware update under OS X 10.15.1

https://skippy.org.uk/continuing-with-pycom-and-a-small-hiccup/