I see a similar problem with 12.04 on an HP EliteBook 8530w:
Kernel Linux 3.5.0-45-generic
Release 12.04 (precise) 32-bit
On Firewire insertion, nothing happens and the disk does not start.
If I then plug the disk using USB 2, the disk starts and works.
If I then unplug the USB cable, then plug the Firewire cable again, this time, the disk starts, gets properly automounted, and works perfectly until shutdown.
I see a similar problem with 12.04 on an HP EliteBook 8530w:
Kernel Linux 3.5.0-45-generic
Release 12.04 (precise) 32-bit
On Firewire insertion, nothing happens and the disk does not start.
If I then plug the disk using USB 2, the disk starts and works.
If I then unplug the USB cable, then plug the Firewire cable again, this time, the disk starts, gets properly automounted, and works perfectly until shutdown.