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* Hold Command-S while booting, to reach single-user mode. Wait for "localhost:/ root# " prompt.
*Connect FireWire HDD and wait 10 seconds. (10 earth seconds; use a stopwatch)
* "ioreg" shows the drive is discovered and all drivers loaded. However, "mount" shows no sign of the FireWire drive.
* If you are willing to "sh /etc/rc" at this time, you can then (when that's done) make the FireWire drive mount by entering "diskutil mountDisk disk1" (assuming disk1 is where the FireWire drive shows up; use "diskutil list" first if you're unsure, but only after "sh / etc/rc"). Now all the volumes appear in /Volumes, mounted read-write.