Well, I never had good days with Firewire and linux, don't know how is the kernel support at the present moment, but I think this could be something more deep to fix, maybe only with a new kernel install, and when comes to new kernel install you can wait to see many things happens beside this firewire issue. Apple is practly an expert when it comes to firewire devices so you we can expect that you hardware is a litle different from the normal... well, I havent any mac here to see the lspci output maybe you could show us what is you hardware with lspci ?
Try to find anythings about you hardware support and issues at
http://www.linux1394.org/ and maybe there you could find a better support to your problem, but I would not expect much.
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