Hardware Reference
In-Depth Information
$ sudo cp -a bootcode.bin fixup.dat start.elf /mnt/raspi-boot/
Whichever method you prefer is fine, as they are both valid methods for
Linux operations as the root user. We use the
su -c
syntax in most examples
throughout the topic for all root operations because it will work in all cases,
whereas
sudo
works only if it is configured for your user on that Linux dis-
tribution. If you an encounter instructions prefaced with
sudo
, know that
su
is an option when you don't have
sudo
configured.
When the new Raspberry Pi firmware finishes copying onto the boot partition, run the
sync
command to ensure the data has all arrived onto the SD card:
$ sync
Then it should be safe to unmount the SD card partition(s) and eject the SD card. You
can unmount these partitions from the GUI interface of your Linux laptop, or you can
manually unmount them from the terminal by changing into a directory that is not in
either of the mounted partitions and then enter:
$ cd ~
$ su -c 'umount /mnt/raspi-boot'
$ su -c 'umount /mnt/raspi-root'
At this point, the SD card will contain the new firmware. You'll know that the update
worked if the Raspberry Pi still boots into the Linux image, but at a minimum, the
firmware will draw a multicolored “rainbow” box (see
“Somewhere Over the Rain-
bow...”
sidebar) to the configured output device (usually an HDMI connected one) as
its first step in the boot process (unless you have explicitly disabled this behavior in
config.txt
). If that occurs, the firmware is properly installed onto the SD card.
Somewhere Over the Rainbow…
Hopefully, if everything goes well with your Raspberry Pi, you'll never have
to see the “rainbow” screen (shown in
Figure 1-3
) for more than a fraction
of a second when it boots up. The screen is generated by the Raspberry Pi
firmware as it initializes the GPU component of the BCM2835 system-on-
chip.
To test that the output works successfully, the GPU draws four pixels on the
screen and then scales those pixels to be very large, resulting in the multi-
color screen. If your Raspberry Pi ever refuses to go over the rainbow and
into a proper Linux boot, it means that the configured Linux kernel image
(default:
kernel.img
) was not able to boot.
