The Cardputer v1.1 is a high-performance card computer for engineers featuring the StampS3A microcontroller, 56-key keyboard, 1.14-inch TFT screen, and various connectivity options for prototyping, industrial control, and IoT projects.
do not use hub but do reboot between two successive installs
hub will provide power (even unpowered hub) for testing but not enough for stable operation, which must be negotiated.
eventually i stopped getting errors about pre-load etc from
sudo kextutil -tn /Library/Extensions/SiLabsUSBDriver.kext