Hi. An ISO image cannot not be booted from BIOS

Initial device state:

# parted /dev/sdc unit s print free
Model: (...) (scsi)
Disk /dev/sdc: 15638480s
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags:

Number Start End Size Type File system Flags
2s 15638479s 15638478s Free Space

Then commands executed were (Note: a non-live ISO image is involved):

# dd if=debian-9.7.0-amd64-DVD-3.iso of=/dev/sdc bs=4M oflag=direct && sync
$ df -hT | tail -n1
/dev/sdc iso9660 4.4G 4.4G 0 100% /run/media/yk/Debian 9.7.0 amd64 3
# parted /dev/sdc unit s print free
Error: /dev/sdc: unrecognised disk label
Model: (...) (scsi)
Disk /dev/sdc: 15638480s
Sector size (logical/physical): 512B/512B
Partition Table: unknown
Disk Flags:

That dd command was also executed without option/parameter 'oflag=direct'. but final result remained identical. I could notice that dd erased existent partition table and didn't add flag boot. Once at last the system was rebooted, then proper device selected from BIOS , the following message was produced:

Reboot and select proper boot device or insert boot media in selected boot device and press a key.