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 <sect1 condition="bootable-usb" id="boot-usb-files">
 <title>Preparing Files for USB Memory Stick Booting</title>

<para>

To prepare the USB stick, you will need a system where GNU/Linux is
already running and where USB is supported. With current GNU/Linux systems
the USB stick should be automatically recognized when you insert it. If
it is not you should check that the usb-storage kernel module is loaded.
When the USB stick is inserted, it will be mapped to a device named
<filename>/dev/sdX</filename>, where the <quote>X</quote> is a letter
in the range a-z. You should be able to see to which device the USB
stick was mapped by running the command <command>dmesg</command> after
inserting it. To write to your stick, you may have to turn off its write
protection switch.

</para><warning><para>

The procedures described in this section will destroy anything already
on the device! Make very sure that you use the correct device name for
your USB stick. If you use the wrong device the result could be that all
information on for example a hard disk could be lost.

</para></warning>

  <sect2 id="usb-copy-isohybrid" condition="isohybrid-supported">
  <title>Preparing a USB stick using a hybrid CD or DVD image</title>
<para>

Debian CD and DVD images can now be written directly to a USB stick,
which is a very easy way to make a bootable USB stick. Simply choose
a CD or DVD image (such as the netinst, CD-1, DVD-1, or netboot) that will fit
on your USB stick. See
<xref linkend="official-cdrom"/> to get a CD or DVD image.

</para><para>

Alternatively, 
for very small USB sticks, only a few megabytes in size, you can download
the <filename>mini.iso</filename> image from the <filename>netboot</filename>
directory (at the location mentioned in <xref linkend="where-files"/>).

</para><para>

The CD or DVD image you choose should be written directly to the USB stick,
overwriting its current contents. For example, when using an existing
GNU/Linux system, the CD or DVD image file can be written to a USB stick
as follows, after having made sure that the stick is unmounted:

<informalexample><screen>
<prompt>#</prompt> <userinput>cp <replaceable>debian.iso</replaceable> /dev/<replaceable>sdX</replaceable></userinput>
<prompt>#</prompt> <userinput>sync</userinput>
</screen></informalexample>

Information about how to do this on other operating systems can be found in
the <ulink url="&url-debian-cd-faq-write-usb;">Debian CD FAQ</ulink>.

</para><important><para>

The image must be written to the whole-disk device and not a
partition, e.g. /dev/sdb and not /dev/sdb1.
Do not use tools like <command>unetbootin</command> which alter the image.

</para></important><important><para>

Simply writing the CD or DVD image to USB like this should work fine
for most users. The other options below are more complex, mainly for
people with specialised needs.

</para></important>

<para>

The hybrid image on the stick does not occupy all the storage space, so
it may be worth considering using the free space to hold firmware files
or packages or any other files of your choice. This could be useful if
you have only one stick or just want to keep everything you need on one
device.

</para><para>

Create a second, FAT partition on the stick, mount the partition
and copy or unpack the firmware onto it. For example:

<informalexample><screen>
# mount /dev/<replaceable>sdX2</replaceable> /mnt
# cd /mnt
# tar zxvf <replaceable>/path/to/</replaceable>firmware.tar.gz
# cd /
# umount /mnt
</screen></informalexample>

</para><para arch="not-s390">

You might have written the <filename>mini.iso</filename> to the USB
stick. In this case the second partition doesn't have to be created as,
very nicely, it will already be present. Unplugging and replugging the
USB stick should make the two partitions visible.

</para>



  </sect2>

  <sect2 id="usb-copy-easy">
  <title>Manually copying files to the USB stick</title>
<para>

An alternative way to set up your USB stick is to manually copy
the installer files, and also a CD image to it.
Note that the USB stick should be at least 1 GB in size (smaller
setups are possible if you follow <xref linkend="usb-copy-flexible"/>).

</para><para>

There is an all-in-one file <filename>hd-media/boot.img.gz</filename>
which contains all the installer files (including the kernel)
<phrase arch="x86">as well as <classname>syslinux</classname> and its
configuration file</phrase>
<phrase arch="powerpc">as well as <classname>yaboot</classname> and its
configuration file</phrase>.

</para><para>

Note that, although convenient, this method does have one major
disadvantage: the logical size of the device will be limited to 1 GB,
even if the capacity of the USB stick is larger. You will need to
repartition the USB stick and create new file systems to get its full
capacity back if you ever want to use it for some different purpose.

</para><para arch="x86">

To use this image simply extract it directly to your USB stick:

<informalexample><screen>
# zcat boot.img.gz &gt; /dev/<replaceable>sdX</replaceable>
</screen></informalexample>

</para><para arch="powerpc">

Create a partition of type "Apple_Bootstrap" on your USB stick using
<command>mac-fdisk</command>'s <userinput>C</userinput> command and
extract the image directly to that:

<informalexample><screen>
# zcat boot.img.gz &gt; /dev/<replaceable>sdX2</replaceable>
</screen></informalexample>

</para><para>

After that, mount the USB memory stick
<phrase arch="x86">(<userinput>mount
/dev/<replaceable>sdX</replaceable> /mnt</userinput>),</phrase>
<phrase arch="powerpc">(<userinput>mount
/dev/<replaceable>sdX2</replaceable> /mnt</userinput>),</phrase>
which will now have
<phrase arch="x86">a FAT filesystem</phrase>
<phrase arch="powerpc">an HFS filesystem</phrase>
on it, and copy a &debian; ISO image (netinst or full CD) to it.
Unmount the stick (<userinput>umount /mnt</userinput>) and you are done.

</para>
  </sect2>

  <sect2 id="usb-copy-flexible">
  <title>Manually copying files to the USB stick &mdash; the flexible way</title>
<para>

If you like more flexibility or just want to know what's going on, you
should use the following method to put the files on your stick. One
advantage of using this method is that &mdash; if the capacity of your
USB stick is large enough &mdash; you have the option of copying any
ISO image, even a DVD image, to it.

</para>

&usb-setup-x86.xml;
&usb-setup-powerpc.xml;

  </sect2>

 </sect1>