It highlights ok, I click on Restart, and it boots from the internal drive. same thing happens with both the OSX and the 9.2 folders - it always boots off the internal OSX. I have also tried different cables and the other FW port.
The firmware on the (brand new!) LaCie needed updating - done. But I still can't get the computer to boot off it. Do I now need to create a fresh SD backup?
This Apple Knowledge base doc:
http://docs.info.apple.com/article.html?artnum=58606
...says G4 PowerMacs PCI graphics will not boot from a firewire drive. Can you tell from my system profile if this is my model - am confused..!