Re-bonjour :-)
sudo dd if=var/run/demo.iso of=/dev/ bs=8M conv=fsync
I am pretty sure it will not work... iso are for DVD, not USB sticks.
Well I guess "ISO" should be taken in a generic sense. I, like other Genodians, have been writing "iso" files to USB thumbdrives for years (Genode, Haiku, and others projects do release "iso" images all the time). The key is that the .iso file should be a hybrid (sp?), that is to say, generated with special parameters passed to xorriso or other tools, so as to integrate not only iso9660 machinery but also a GPT or MBR layout so that it can be written equally well to an HDD or USB stick and work correctly.
You can convince yourself of that by downloading a pre-built Sculpt OS iso image and test it... On bare metal or in VirtualBox. It should boot up equally well (or not) as other bootable USB sticks.
Beside .iso's there is also another way to generate .raw or .img files that do *not* have iso9660 compatbility IIRC, so that should work too.
Cédric