Startup from USB drive

Hi All

I would like to startup from an external USB drive. I have managed to restore a .dmg image of a workable "emergency" OS/X onto it but when using system preferences to select it as a startup, it is listed but it doesn't seem to want to restart and just sits there

I have done it with a FireWire disk with no problem - is there a problem with using USB drives?

I have an iBook G4 933Mhz - 2 USB - and a Boot ROM version of 4.7.7f0

HELP!!

Paul

Have you tried holding the option key on reboot? This will bring up a list of bootable drives that your mac sees. Is your USB harddrive USB2.0? That also could be your problem

Im not sure if usb is fast enough to boot from, is it usb 2 or 1.1?

Hi

Its a USB 2.0 drive

I've tried holding down "t" at startup and that shows my main internal drive - I've also held down the option key - again it does not show the external drive... hmmm.

pavlaki62 said:

Hi

Its a USB 2.0 drive

I've tried holding down "t" at startup and that shows my main internal drive - I've also held down the option key - again it does not show the external drive... hmmm.

Click to expand...

how is the drive formatted, it has to be hfs+ which is mac os extended to be used as a bootable volume.

Hi *

It was formatted as MAC HFS (Journaled) - System Preferences sees it as a valid OS/X startup choice.

What is interesting is that if I try to install OS/X on the USB drive, Installer reports that it will not be bootable. Interesting...

Question: - is just simply not possible to boot from certain USB devices? Is it because the USB subsystem is only available at a certain boot level? whereas FireWire is available at a much lower system level?

hmm, how much space is available? I think theres a minimum space requirement when booting from a small external device. like for writing virtual memory/swap files, I think its like the size of the os, so about 3 gigs or so.

Hi *

Its a 37Gb drive - formatting it to MAC HFS (journaled) and then trying to install OS/X on it with the Apple Software Install CD still results in Installer marking it with a red exclamation mark telling me that it will not be bootable.

As I said, had no problem with my FireWire drive - that works beautifully ... just wondered if anyone has managed to start OS/X from a USB drive or is it just me that is not having luck