the whole unetbootin thing baffles me. i know there are people who can get it to work, however i have never once gotten a bootable usb stick out of it with ANY distro. and it sure wasnt for lack of trying when i finally gave up.
with that being said the official supported method for creating a usb stick from inside linux is the above process. i wrote a how-to on our bitbucket not long ago but i cant find it atm. if anyone with more luck with unetbootin than me would like to do a how-to please feel free. actually we could use a how-to for making a bootable stick from inside windows too but i havent run windows in roughly 10 years so again thats outside of my knowledge