Firewire drive startup problem: OSX 10.4.7

[edoates]

I just erased (diskutility) a Firewire drive (both the "drive" and the "partition" on a drive (Wiebetech Duo-800(500GB)) drive which as booted successfully with Superdrive clones before.

But this time, no joy. The "dev" folder appears when I open the drive with Finder; as I understand it, this folder should be invisible for bootable drives.

I did a "smart" update to the newly erased drive with the "backup all files" settings.

The drive appears on the system preferences Startup preference panel, but not on the "option restart" list. When the Startup Preference is set to this drive, the gray startup screen shows the folder with the question mark icon, before booting from my internal drive.

Any clues as to what I've done incorrectly here?

Just before this, I cloned a safety (offsite) backup by just erasing the drive with DiskUtility, then backing up. It booted fine.

Ed