Re: hdd image does not support uefi?

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

Hi,

donotemailme@xganon.com wrote:
> The documentation suggests to
> cp iso to /dev/sdX
> Then add a partition to /dev/sdX for persistent storage.
> 
> This does not work. If you cp or dd the iso to the block device the block
> device is identified as an ISO and you can not add a partition to it.

Which partition editor exactly refuses to add a partition after
plainly copying the ISO onto a disk-like storage device ?
What are its refusal messages ?


> If you partition the block device first then cp or dd the iso to the
> /dev/sdX1 it sometimes works and boot

This would be a surprise. Are you sure that it was not other software
which booted ?


> [...] writing partitions to a partition
> is a very edge case thing.

Actually this is not supposed to make the partitions within the ISO
visible as partitions of the storage device.
What partition table type was used ? MBR/DOS or GPT ?


> I tried a lot of things to produce a usb disk where the iso and the
> persistent storage were both on the same device

Did you already consider to add a partition by writing a few bytes to
the MBR/DOS partition table of the Debian-Live ISO ?

The new partition entry would consist of 16 bytes beginning at byte 478
of the ISO image.
It is quite a safe bet that this century's firmware will ignore the
C/H/S fields. So you'd have to fill in only partition type (e.g. 0x83),
LBA of first absolute sector, and number of sectors.
The latter two are little-endian 32 bit numbers counting blocks of
512 bytes size.
See
  https://en.wikipedia.org/wiki/Master_boot_record
section
  Partition table entries


Have a nice day :)

Thomas