This short tutorial assumes you build the bootable USB from a Linux system (not from Windows or Mac).
– First make an hybrid ISO from your distro .iso file using isohybrid tool. This step isn’t required if your .iso are already a hybrid.
$ isohybrid your_iso_file.iso
You might see an error when issuing the command
Warning: more than 1024 cylinders (1620).Not all BIOSes will be able to boot this device
Don’t worry about it.The warning refers to very old BIOSes.
– Then use dd to write that hybrid ISO to your USB drive.
$ dd if=your_iso_file.iso of=/dev/sdX
your_iso_file with the name of your .iso file.
/dev/sdX with the path to the USB drive. Note: the path to the USB drive (/dev/sdX) you want to write to must not contain a partition letter. So it should look like /dev/sdb not /dev/sdb1.
Also, the dd command does not provide indicator for progression while it is running in the console. Just wait for a little while.
Create USB Boot Stick | PCLinuxOS forum
HOWTO: Create a bootable Linux Media using the dd Command | Toolbox.com