How to create a bootable USB flash with Ubuntu when all other fail

The situation:

• Dell mini 9
• Freshly installed Ubuntu 11.04 

My goal:

Creating a bootable USB flash from an ISO image file (e.g.: Clonezilla).

So I installed UNETbootin to solve my ISO to USB-flash problem. But although it reported no error during the whole process every time when I actually wanted to boot from the USB flash I always got the message “Disk is not bootable!”.
(Looking back now I guess the granted rights for UNETbootin on my machine might not have been enough. That’s weird because I always had to enter my user password during the application start.)

My workaround by hand:

How to create a bootable USB flash with Ubuntu:

1. Right-click USB flash on your desktop and format it.
   Compatible with all systems (FAT)
2. Open “Terminal”
3. mount
   find out the exact device name.
    
   !!! Make sure to have the right device for the next steps !!!
   In my case the USB flash was “/dev/sdb1”.
     
4. umount /dev/sdb1
   (it worked even mounted btw…)
5. sudo syslinux /dev/sdb1
   if you do not have it, install the package first
6. sudo dd if=/usr/lib/syslinux/mbr.bin of=/dev/sdb 
   I use the device itself and not just a partition to write to the mbr.
7. Congratulations! You have a bootable USB flash now…

Copying the ISO contents to the USB flash:

• Back to the desktop:
  Because my device was unmounted I pulled it out and plugged it in again. It should have a file called “lslinux.sys” on it now.
• I now double-clicked the ISO-File (e.g. Clonezilla) in one window and had my USB flash in another window of the file browser.  
  “View / Show Hidden Files” was activated.
• After that I just dragged and dropped all the content from the ISO right onto my USB flash.
• Time for a reboot and choose the USB flash as booting device. Voila!

This should actually make any other linux ISO bootable on a USB flash as-well.