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  <sect2 arch="any-x86" id="bios-setup"><title>Invoking the BIOS/UEFI Set-Up Menu</title>

<para>

The BIOS/UEFI provides the basic functions needed to boot your machine and
to allow your operating system to access your hardware.  Your system 
provides a BIOS/UEFI setup menu, which is used to configure the BIOS/UEFI.
To enter the BIOS/UEFI setup menu you have to press a key or key combination
after turning on the computer. Often it is the <keycap>Delete</keycap>
or the <keycap>F2</keycap> key, but some manufacturers use other keys.
Usually upon starting the computer there will be a message
stating which key to press to enter the setup screen.

</para>
  </sect2>
  
  <sect2 arch="any-x86" id="boot-dev-select-x86"><title>Boot Device Selection</title>

<para>

Within the BIOS/UEFI setup menu, you can select which devices shall be
checked in which sequence for a bootable operating system. Possible choices
usually include the internal harddisks, the CD/DVD-ROM drive and USB mass storage
devices such as USB sticks or external USB harddisks. On modern systems there
is also often a possibility to enable network booting via PXE.

</para><para>

Depending on the installation media (CD/DVD ROM, USB stick, network boot)
you have chosen you should enable the appropriate boot devices if they
are not already enabled. 

</para><para>

Most BIOS/UEFI versions allow you to call up a boot menu on system startup in
which you select from which device the computer should start for the
current session. If this option is available, the BIOS/UEFI usually displays
a short message like <quote>press <keycap>F12</keycap> for boot
menu</quote> on system startup.
The actual key used to select this menu varies from system to system;
commonly used keys are <keycap>F12</keycap>, <keycap>F11</keycap> and
<keycap>F8</keycap>. Choosing a device from this menu does not change
the default boot order of the BIOS/UEFI, i.e. you can start once from a
USB stick while having configured the internal harddisk as the normal
primary boot device.

</para><para>

If your BIOS/UEFI does not provide you with a boot menu to do ad-hoc choices
of the current boot device, you will have to change your BIOS/UEFI setup to make
the device from which the &d-i; shall be booted the primary boot device.

</para><para>

Unfortunately some computers may contain buggy BIOS/UEFI versions. Booting &d-i; from
a USB stick might not work even if there is an appropriate option in the
BIOS/UEFI setup menu and the stick is selected as the primary boot device.  On
some of these systems using a USB stick as boot medium is impossible; others
can be tricked into booting from the stick by changing the device type in
the BIOS/UEFI setup from the default <quote>USB harddisk</quote> or <quote>USB
stick</quote> to <quote>USB ZIP</quote> or <quote>USB CDROM</quote>. 
<phrase condition="isohybrid-supported">
In particular if you use an isohybrid installation image on a USB stick
(see <xref linkend="usb-copy-isohybrid"/>), changing the device type to
<quote>USB CDROM</quote> helps on some BIOSes which will not boot from a USB stick in 
USB harddisk mode.</phrase>
You may need to configure your BIOS/UEFI to enable <quote>USB legacy support</quote>.

</para><para>

If you cannot manipulate the BIOS/UEFI to boot directly from a USB stick you
still have the option of using an ISO copied to the stick. Boot &d-i;
using <xref linkend="boot-drive-files"/> and, after scanning the hard
drives for an installer ISO image, select the USB device and choose an
installation image.

</para>
  </sect2>

