So with the new 4.1.0 cgminer these 2 lines are what I get spammed after 10secs:
HFB 0 HFGetHeader usb read err:(-1) LIBUSB_ERROR_IO
HFB 0 attempted reset got err:(0) LIBUSB_SUCCESS
No errors like this with 3.11.0. Firmware issue? I still have original firmware from batch 2 shipment.
Try the .4 firmware; it helps reduce LIBUSB errors.