Resolution

Connect the FireWire device and the computer with a single FireWire cable that you know works properly.

FireWire hubs can be used as standalone devices or can be incorporated into displays, external hard drive enclosures, and other devices.  Although the FireWire specification allows for dozens of devices to be connected at the same time, each additional device may add the possibility of unexpected behaviors. For this reason, a direct connection without a hub is suggested if your configuration requires troubleshooting.