You can use
sudo umount /dev/sd<?><?>
<?><?> is a letter followed by a number, look it up by running
It will look something like
sdb 8:16 1 14.9G 0 disk
├─sdb1 8:17 1 1.6G 0 part /media/username/usb volume name
└─sdb2 8:18 1 2.4M 0 part
I would dismount sdb1.
Then, next (this is a destructive command and wipes the entire USB drive with the contents of the iso, so be careful):
sudo dd bs=4M if=path/to/input.iso of=/dev/sd<?> conv=fdatasync status=progress
input.iso is the input file, and
/dev/sd<?> is the USB device you're writing to (run
lsblk to see all drives to find out what
<?> is for your USB).
This method is fast and has never failed me.
EDIT: for those on a Mac ending up here, use lowercase for
sudo dd if=inputfile.img of=/dev/disk<?> bs=4m && sync
EDIT: If USB drive does not boot (this happened to me), it is because the target is a particular partition on the drive instead of the drive. So the target needs to be /dev/sdc and not dev/sdc
<?> For me it was /dev/sdb .
Reference: https://superuser.com/a/407327 and https://askubuntu.com/a/579615/669976
How to make a dedicated Unity USB Stick
Step 1: Download the latest Daily Natty image
Step 2: Create the USB stick installation
When you start the application, it will likely automatically find the ISO you downloaded, which is displayed in the top pane. If you don’t see it, click the Other button and go and select the ISO (typically in your Downloads/ directory in your home directory).
It is recommended you first erase your USB stick, so select it in the bottom pane and click the Erase Disk button. When this is complete, you can then use the slider underneath the Stored in reserved extra space slider to select how much disk space can be used for saving files, documents and other things. Depending on the size of your USB move the slider all the way to the right to use the maximum space available.
Finally, click the Make Startup Disk button and Natty will be installed to your USB stick.
Step 3: Boot into the Key
Now you need to boot from USB stick. To do this you may need to enter your BIOS to enable your computer to be able to boot from the USB stick. When this is enabled you will typically need to hit a button when you boot to see the BIOS’s boot menu and then you can select the USB drive.
Ubuntu should boot and look and function the same as usual, apart from being much slower as you are running from the USB disk.
Step 4: Update and Prepare the Key
Although you installed the latest daily you should ensure it is up to date, and you can do this with:
From now on you can update the key daily to keep it up to date. Now you need to enable apport so that when something crashes it can report it to Launchpad:
Edit /etc/default/apport, set and set enabled=1.
Step 5: Test and Report Bugs
Filing a bug is simple. Just open a terminal and run:
The ubuntu-bug program zips up some debugging data from your system and will then fire up a page in your browser where you can enter a bug report. This will then provide details of the problem to the Unity developers to help fix the bug.
Ubuntu Liveusb Wiki