"To erase the ISO 9660 superblock of debian-9.3.0-amd64-netinst.iso do
umount /dev/sde1 dd if=/dev/zero bs=2048 seek=16 count=4 conv=notrunc of=/dev/sde But first make sure that /dev/sde is indeed the medium you want to erase." I did that before the result is : dd if=/dev/zero bs=2048 seek=16 count=4 conv=notrunc of=/dev/sde Same answer with fdisk cfdisk ... Sorry