In terminal we will use dd command for creating a live bootable usb. 1st of all, lets find out our usb device.

sudo fdisk -l

That will list down your storage devices.

NOTE: Before doing this, please backup your files from the usb as it will erase the device.

Now type the following command while changing the paths:

dd if=/path/to/iso-file of=/dev/sdc

bs can be added to the end of the command, bs{byte size}. bs=4096 OR bs=2048

dd if=/path/to/iso-file of=/dev/sdc bs=2048

Remember to not include the integer for the device, as it is representing the partition like sdc1 or sdc2 etc. Just use the device name like /dev/sdc or /dev/sdf.