Since 0.5 up to 0.10.2, every published Tails i386 ISO image has been a hybrid one:

- it can be burnt to a DVD;
- it also contains a full disk image (including partition table) and
  can thus be copied (using `dd`) to a USB stick; the USB stick's
  content is lost in the operation.

Then, we stopped hybrid'ing the ISO images we publish, and started
again in Tails 1.3.

Nowadays, we pass the `-h 255 -s 63` options to `isohybrid`, as
advised by the syslinux community for images between 1 GiB and
4 (?) GiB.

Archives
========

What follows comes from the Tails 0.10 days.

Successful tests:

* boot the resulting `test.iso` as a normal optical drive in
  VirtualBox
* boot the resulting `test.iso` as a KVM hard disk
* convert the resulting `test.iso`, posing as a HDD image, into the
  native VirtualBox disk format, using `VBoxManage
  convertfromraw -format VDI test.iso test.vdi`, then boot the
  resulting `test.vdi` disk image in VirtualBox
* `dd` the hybrid `test.iso` to a USB stick and boot it on
  a USB-boot-enabled computer.

Notes:

* the partition number may need to be 4, in order to be compatible
  with the BIOSes supporting only USB-Zip;
  [reference](http://syslinux.zytor.com/archives/2009-May/012380.html)
* the partition type may need to be `1c`, i.e. hidden FAT32 LBA;
  [reference](http://syslinux.zytor.com/archives/2009-May/012384.html)
* boot failures were experienced when testing without the `-entry
  4 -type 1c` options.

Conclusion: this is a nice way to get bootable USB images for almost
free.
