I would like to create a bootable Linux ISO on a USB drive under Debian 9. I found that the ISO is only bootable if it has been written to the disk
If the ISO is written to a specific partition, e.g. /dev/sdd1, then it is not bootable. What is the technical reason behind this?
It works after writing the ISO to a partition and deleting the partition afterwards using Gnome-Disk, this does not delete the file, but makes the disk bootable.