Preparing Files for USB Memory Stick Booting
There are two installation methods possible when booting from USB stick.
The first is to only use the USB stick to boot the installer, and then
install completely from the network. The second is to also copy a CD image
onto the USB stick and use that as a source for packages, possibly in
combination with a mirror.
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
/dev/sdX, where the X
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 dmesg after
inserting it. To write to your stick, you may have to turn off its write
protection switch.
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.
To prepare a USB stick that only boots the installer, which then proceeds
to install entirely from the network, you'll need to download the
mini.iso image from the netboot
directory (at the location mentioned in ), and
write this file directly to the USB stick, overwriting its current contents.
This method will work with very small USB sticks, only a few megabytes in
size.
For example, when using an existing GNU/Linux system, the
mini.iso file can be written to a USB stick as follows:
# cat mini.iso > /dev/sdX
# sync
To add firmware to a USB stick prepared in this way, obtain the necessary firmware
files. See for more information.
Now unplug and replug the USB stick, and two partitions should now be visible on it.
You should mount the second of the two partitions, and unpack the firmware onto it.
# mount /dev/sdX2 /mnt
# cd /mnt
# tar zxvf /path/to/firmware.tar.gz
# cd /
# umount
To prepare a USB stick that installs packages from a CD image included
on the stick, use the installer images found in the
hd-media directory. Either the easy
way
or the flexible way
can be used to copy the
image to the USB stick. For this installation method you will also need
to download a CD image. The installation image and the CD image must be
based on the same release of &d-i;. If they do not match you are likely
to get errors
The error message that is most likely to be displayed is that no kernel
modules can be found. This means that the version of the kernel module
udebs included on the CD image is different from the version of the
running kernel.
during the installation.
Note that the USB stick should be at least 256 MB in size (smaller
setups are possible if you follow ).
Copying the files — the easy way
There is an all-in-one file hd-media/boot.img.gz
which contains all the installer files (including the kernel)
as well as syslinux and its
configuration file
as well as yaboot and its
configuration file.
Note that, although convenient, this method does have one major
disadvantage: the logical size of the device will be limited to 256 MB,
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.
A second disadvantage is that you cannot copy a full CD image onto
the USB stick, but only the smaller businesscard or netinst CD images.
To use this image simply extract it directly to your USB stick:
# zcat boot.img.gz > /dev/sdX
Create a partition of type "Apple_Bootstrap" on your USB stick using
mac-fdisk's C command and
extract the image directly to that:
# zcat boot.img.gz > /dev/sdX2
After that, mount the USB memory stick
(mount
/dev/sdX /mnt),
(mount
/dev/sdX2 /mnt),
which will now have
a FAT filesystem
an HFS filesystem
on it, and copy a &debian; netinst or businesscard ISO image to it.
Unmount the stick (umount /mnt) and you are done.
Copying the files — the flexible way
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 — if the capacity of your
USB stick is large enough — you have the option of copying a
full CD ISO image to it.
&usb-setup-x86.xml;
&usb-setup-powerpc.xml;
Booting the USB stick
If your system refuses to boot from the memory stick, the stick may
contain an invalid master boot record (MBR). To fix this, use the
install-mbr command from the package
mbr:
# install-mbr /dev/sdX