CLI: Bootable USB From ISO
Check if flash drive is properly plugged and identify its label (something like /dev/sda):
sudo fdisk -l
Run dd command to make a bootable USB from the ISO file:
sudo dd bs=4M if=/path/to/file.iso of=/dev/sdX status=progress oflag=sync
Replace /path/to/file.iso with the path to your ISO file and replace /dev/sdX with the name of your device.