I find Unetbootin to be a great utility to create Live USBs once the distro or utility you want is already included in the list of Unetbootin's built-in distros.
It is particularly useful with my Asus EeePC 901 which has no CDROM.
However, in addition to a list of built-in distros, the "create LiveUSB" dialog contains an option to create directly from a downloaded ISO. This has never worked for me.
In particular, I wanted to install Syllable OS on the EeePC. The creation of the LiveUSB from the ISO gave no errors but when I tried to use it, I got this message:
I got almost the same message after I had apparently successfully created a LiveUSB of DragonflyBSD from the ISO and then tried to use it.
I read somewhere that the Windows version of Unetbootin is easier to use and less prone to surprises than the linux version (which is what I had been using).
So, I created a LiveUSB of Syllable OS using the Windows version of Unetbootin. Unfortunately, once again I got the same error message when I tried out the USB.
So, what's going on here? Does Unetbootin work with downloaded ISO's or not? Anybody had success with this and can maybe point to where I'm possibly slipping up?
I even wrote to Unetbootin's developer about this problem as I see this as such a useful tool for EeePC-users. However, I haven't yet received a reply.
Thanks for any advice or comments

I can affirm that Unetbootin can successfully create bootable USB keys from downloaded ISO images. A couple of times I've had to go into the /casper directory on the USB key and change references to "/cdrom" to -- as I recall -- ./ (since the files referred to are right there and not on a CDROM). Then it worked. Other times there was nothing extra to do.

I wonder if you're using the EeePC to download the .iso and to attempt to create the USB medium using unetbootin. I haven't tried that. I have created the USB keys using my desktop computer or the laptop I have that runs regular Ubuntu 8.04 (Hardy Heron). If you have access to another machine -- assuming you were using EeePC all the way -- it might be worthwhile to experiment that way.

Sorry I can't think of any other suggestions. If the MD5sum from the image matches the one provided on the download site, the image should be OK as far as I know.

Thanks for your reply.
In general, I use the EeePC 901 to create LiveUSBs but I did switch to my Dell Desktop to use the Windows version of Unetbootin. However, this too gave me an unbootable LiveUSB version of Syllable.
In any event, doesn't hurt to try out your suggestion to prepare the LiveUSB from Ubuntu Hardy on my Dell.
However, got the very same result -- although the LiveUSB of Syllable seemed to be created without even an indication of an error, when I tried to use it on the EeePC, I just got
Has anybody else other than me ever seen this when using Unetbootin?

I'll try making a USB key of the live Syllable OS (which I hadn't heard of till this thread) probably later today and report back here if it worked for me. I don't imagine it will.

I wasn't able to create a USB key using unetbootin with the SyllableOS live CD ISO. It dawned on me after this failure that SyllableOS is not a Linux distro, therefore maybe unetbootin won't work with it. Still, it appears you got something written to your USB device... I didn't. Just out of curiosity I'll burn a CD-ROM from the ISO image and see what happens. I won't be able to try it out on my EeePC, however -- no external CD-ROM drive here.
Stay tuned...

I was able to run the SyllableOS live version from CD-ROM. So the image is OK. Not a bad-looking system. It dealt successfully with my Everex gBook's 1440x900 display, which is more than I can say for Ubuntu 8.10 (boo!). The default mouse/touchpad values were acceptable, too. I didn't look around all that much; the only network connection supported at this point in development is wired Ethernet, and I'm a wireless person. I looked at the text editor and it worked....

It would be fun to see what it did on the EeePC. Maybe you'll find an alternate method of making the USB live image. I hope so; sorry I don't have any more suggestions to offer.

Thanks for your replies and your very active participation in the details of my problem.
However, I'm surprised that Unetbootin wrote nothing at all to your key.
Note that there are two current versions of Syllable. You probably used 0.6.5 while I used the "development" version 0.6.6 which you can get here.
Did Unetbootin spit out any error messages when you used it with Syllable?
Anyway, it seems that Unetbootin uses the syslinux bootloader which doesn't agree with Syllable.
So, I did a Grub setup to the mbr of the usb-key and now it boots -- at least partially.
The boot still errored out about half way through because of problems with the Syllable usb driver. But at least, I can now see that it never was a Unetbootin problem.
My interest in Syllable arises because I believe that small, very fast-booting and "lite" OSes such as this are ideally suited to netbooks. I have Senryu and Haiku on my EeePC for the same reason.
Best wishes
Paul

So i have a Sandisk 5gig USB key that had mint 9 live on it that i was hoping to get an old brotasaurus (Dell Latitude D510) up and running again with. apparently Mint is too pretty for the beast and so I tried to get mint Fluxbox to install on to the key, then i tried Fedora, and finaly i tried DSL. Unetbootin seems to have stoped making the key bootable as three of my laps seem unable to read it. I think this may be because i whiped the key with gparted and got rid of the small little boot partition with out even thinking about....any help would be much apreciated


[Update]
so i tried dd'ing the iso to the usb following the instructions on the suse site
# umount /dev/sdb1
# dd if=/home/Derf/Downloads/dsl-4.4.10.iso of=/dev/sdX bs=4M;sync
and it is still failing to create a bootable usb. says missing operating system