You are right, I get a “Failed to connect to AxiDraw. :(” error when trying to access the AxiDraw (lower the pen etc. from the Inkscape extension)). I changed the USB cable, still the same.
If I terminal my mac to list the devices, I don’t find anything remote to the EBB. IOUSBHostDevice IOUSBHostDevice BRCM20702 Hub Bluetooth USB Host Controller Keyboard Hub Apple Keyboard USB-PS/2 Optical Mouse IOUSBHostDevice FaceTime HD Camera (Built-in) MacBook Air SuperDrive