This works under Lubuntu, if you use Windows, please scroll down and under further reading there is a link to a similar How to by Dan Smith on how to do this using unetbootln under Windows.
Creating a boot usb flash disk
(With thanks to Nio Wiklund for some helpful comments with regard to the title of this document)
A good tool for this is Unetbootin, you can install this on most popular Linux distributions,
e.g sudo apt-get install unetbootin
you need your root password.
You can then load the software up, you will need your root password
If you have downloaded an iso image you don’t need to worry about the top section
Click disk image, ISO can be left as in, then click the box with … in and select the iso file
select type, usb drive or hard disk, most people are going to want to create a usb boot flash disk.
drive should be the device reference for this disk
make sure you are 100 percent sure, and if you are not sure ASK on forums , IRC or elsewhere first.
I find it helpful to unmount and unplug my external hdd first, it gives less options but also reduces the chances I will write to it, The disks tool below is useful for finding out what device you are writing to.
If you have already downloaded and md5 checked your iso file then you don’t need to worry about the top part,
Click disk image radio button
the drop down menu to the right of this is a betweet ISO and floppy
you can then click on file search button (the one with … )
Select if you want to have a persistent space for files.
type – you can choose between usb and hard disk (BE VERY CAREFUL)
then select the device, if you select hard disk then the device reference chances to / indicating root of the file system.
REMEMBER that you can wipe your whole file system if you get the options wrong, if you have an external hard disk and a usb disk plugged in I find it helpful to unmount and unplug the external hard disk, gives less target options and is less likely to get wiped by mistake.
You need to check if the target device should be mounted first or not,
Hopefully this how to is useful, please be careful as I am not responsible for data loss, I try and write guides to be generic not explicit guides. I will leave this to the documentation team
You can use fdisk and df to determine device references. Read the man pages for more info if you get stuck as for help and say you have looked at man pages, this blog post etc and are still stuck, this shows you have tried to research the issue.
The ubuntu manual should have this information in it too.
If you need to format the flash disk, using disks, this is a case of
Unmount the flash disk
MAKE SURE YOU HAVE THE RIGHT DEVICE SELECTED.
Once this is all done and you are happy with the destination click OK
Progress bar showing how many files have been copied and a percentage
All done you can now reboot, select usb disk from the boot device menu (see your Manual on how to access this) and tryout / install the new OS
https://help.ubuntu.com/community/Installation/FromUSBStick Wiki Team Unetbootln under windows By Dan Smith