Re: Debian Live USB fails; bricks the USB stick

["Thomas Schmitt" <scdbackup@gmx.net>]

Hi,

> sudo if=debian-live-9.2.0-amd64-cinnamon.iso  of=/dev/sdc

I assume the missing "dd" between "sudo" and "if=" is a copy+paste error.
Elsewise it is the correct copying method.


> I checked the md5sum on the downloaded file (it was correct),

Did you also check the MD5 of the copy on USB stick ?

  dd if=/dev/sdc bs=2048 count=1043616 | md5sum

This has to be done before booting the stick the first time.
If i boot the image with OVMF as virtual firmware, then the MD5 of the
ISO changes. Obviously some data get written into the EFI partition.


> It gave me the grub menu,

So the copying process has probably worked fine.

If the menu is really from GRUB (with a headline saying "GNU/GRUB") and 
not ISOLINUX (with no such headline), then your firmware is EFI in its
native mode.


> but then when I tried to
> boot Debian Live, I got an error about an invalid magic number and a need to
> load a kernel first.

This must be an inner problem of the operating system.

But

  qemu-system-x86_64 -enable-kvm -m 512 \
                     -bios /usr/share/ovmf/OVMF.fd \
                     -hda debian-live-9.2.0-amd64-cinnamon.iso

boots for me through the first item of the GRUB menu and the kernel boot
messages into some graphical desktop.
The option -hda is the equivalent to an USB stick, -cdrom would be the
equivalent of a CD or DVD.

Since i cannot reproduce the problem from your info, you will have to
describe the symptoms and preconditions in more detail.
What's the firmware mode ? EFI or BIOS/Legacy ?
Especially the original error messages will be needed.

Then probably you will have to carry the issue to debian-live mailing list
  https://lists.debian.org/debian-live/


> And now, both my sticks are complaining about being mounted read-only, and I
> can't seem to fix that.

That's just a consequence of the fact that the partitions number 1 of the
sticks bear ISO 9660 filesystems, which are read-only. The stick is still
writable.

You can invalidate the ISO 9660 filesystem by

  dd if=/dev/zero bs=2048 count=1 seek=16 of=/dev/sdc

You may want to change the partitioning and also remove the EFI partition 2.
Then you may create new filesystems in the partitions.

(If you had dd'ed a backup image of the USB stick before dd-ing the ISO onto
 it, then you could dd that image onto the stick to get back the old
 partitions and their filesystems.)


Have a nice day :)

Thomas