Subject: bug#34487: dd (coreutils) 8.30 – A written ISO image cannot not be booted from BIOS

From: Ricky Tigg <[email-masked]>
Date: Fri, 15 Feb 2019 13:02:24 +0100

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.*
>