MacBook Pro: What to do if bus-powered FireWire devices don‘t appear in menus or behave correctly
Your MacBook Pro may not recognize your FireWire device properly—it doesn't appear in menus, it's not recognized or it doesn't behave properly.
If you find this to be the case, the device probably came with an external power supply, and is demanding more power than the FireWire standard provides through the bus. This issue can also appear if a number of FireWire devices are plugged in to the same bus and demand more power than the bus provides.
(Bus-powered devices derive their power from a source on the bus to which they are attached. Self-powered devices come with an AC adapter and plug into a wall socket for power as well as into the computer.)
Be sure always to use the power supply if one came with a FireWire product. If you are connecting more than one device, use a self-powered FireWire hub or switch.