I have tried without success to connect a couple of Firewire 400 devices to my 2012 MBP via the FW 800 port. I am using a Belkin FW 800 cable with a 400 adapter on one end. The connection between the cable and the adapter is a little wiggly and I thought that may be the culprit. I have found through the process of elimination that the cable itself is good as is the FW 800 port on my Mac. I know this because I was able to connect my PowerBook G4 to the MBP in Target Disk mode using the 800 ports on both. I also have an external FW 400 hard drive that will mount fine using a FW 400 cable connected to the aforementioned PowerBook G4. But when I try to connect it to the PBG4 using the 800 adapter at the drive end and connect it to the computer's 800 port it will not mount. Anyway, long way around the barn.... how likely is it that the adapter is responsible for the connection failure? It sounds logical but I have heard of a number of issues with FW 400 talking to 800 and vice versa. Anyone have any similar problems?