Need to boot Linux from USB

Question

I have been trying to get this to work for a while now but it appears with the current firmware it is just not possible to boot a Linux OS from a usb drive.
Is this true? or is there a way it can be done?
Basically I work in a forensic computing lab and as our portable forensic machines we have a total of 16 MacBook Pro's all the same spec set up to dual boot WinXP and Leopard.
So far they've been excellent giving us the benefits of both OS's to run the different forensic tools on.
My problem is i need to boot a linux distro from a portable drive (USB or Firewire is fine but USB would be better) for a particular purpose.
As you can imagine, our system gets filled with loads of rubbish and we need to clean them regularly so i have created an install from a wiped drive containing everything we need on the drive. I have then created some scripts in Linux that use dcfldd to create an image of the entire drive and compress it to about 13GB.
I also created another script that puts the image back on the internal drive.
This basically allows me to put clean "forensically" secure images back on the laptops within about an hour. i can also then update any software etc before creating a new up to date image.
Currently I have to use a Linux boot CD to start the laptop with an external drive attached holding the scripts and image. i would like to just have a bootable thumb drive that holds everything and be able to start from it by holding the option key, put the image on the internal drive and reboot. its very quick except from the booting and running from CD whereas a small puppy linux build or similar would be very quick. And because we sometimes have to do this onsite speed is a major issue.
Am i correct in thinking that the firmware just doesn't allow it or has anyone managed to get this to work?
If it is the firmware, does anyone know if there is an update on the horizon that will remedy this problem?
I should state i have tried many linux builds (using MBR and GPT options etc) and refit and nothing allows the drive to boot with refit stating the firmware has limited support for legacy systems on USB.
I also know that I CAN (and have tried) using a Mac OS installed on the USB drive but it appears to have its own problems. it is fine when the internal drive is empty but because in my case it has an OS on it the system actually seems to use some of the components of the internal drive so when trying to image over it i get conflicts. The Mac OS also takes a lot of room on the drive when i just want a stream lined OS for this job.
The main reason i don't want to use Mac OS though is that i plan to later add images for our doing our lab machines which are PCs and would therefore not boot the Mac OS.
If anyone can help with this I would be grateful.
Cheers
Chris

Answer 1

Most Linux distros will not boot from USB devices as is. I believe you're in luck with Ubuntu because there are some methods of running it from USB flash drives that just may do the trick for you. I ran across this when looking into putting Ubuntu on my MSI Wind.
Boot and run Linux from a USB flash memory stick | USB Pen Drive Linux.webloc;
On the Ubuntu site look for information in the documentation for installing on pendrives.
I'm pretty sure that the methods for booting from USB flash drives will apply to any USB drive. From what I learned Linux simply isn't set up to boot from a flash drive or USB drive without some effort on the part of the installer. I've never done this myself so I can't tell you what to do only some pointers to where you may find how to do it.
After my experience using Ubuntu on my Wind I decided it wasn't worth the effort involved. OS X is simply much better than Linux in every respect. I just wasn't interested in becoming any geekier than I already am. I had enough of that 20 years ago!