Ubuntu create bootable USB from iso

I had problem with my Ubuntu included tool cant flash bootable USB. I don't want to install additional soft, because I'm flashing from various computers. So there is great tool that included in all Ubuntus. It works great.

1. Put USB flash and determine the device it's mounted on with the command:
sudo fdisk -l

Umount the device
umount /dev/sdc1

Now my ISO was using isolinux not syslinux. I knew it worked with CDs so I figured out that I needed to call the isohybrid command, which allows for an ISO to be recognized by the BIOS from a hard drive.
isohybrid filename.iso
You can find out more about this command here, but this was the cause of the message "Missing Operating System" The first problem was fixed, but now it said "isolinux.bin was missing or corrupt"

The next step is to copy the iso. Using device partition, not the actual numbered one.
sudo dd if=filename.iso of=/dev/sdc bs=4k

This seems to work just fine, but the forum where I got the last fix, it was recommended to do the following before unplugging the device:
sync
sudo eject /dev/sdc