I found this fixed my pi hanging issue
add slub_debug=FPUZ to /boot/cmdline.txt
From https://bitcointalk.org/index.php?topic=494625.msg5932931#msg5932931

To keep it running I followed these instructions to make a systemctl service
https://techsparx.com/cryptocurrency/mining/setup-usb-miner-cgminer.html

Edit to add this USB pi thread has had mine running for weeks now after not getting the pi to detect a known working for some else's hub.
https://bitcointalk.org/index.php?topic=843788.0