Hardware Reference
In-Depth Information
$ ls -l
total 8
drwxrwxr-x 3 spot spot 4096 Dec 12 21:57 3.6.10+
drwxrwxr-x 3 spot spot 4096 Dec 12 21:57 3.6.10-cutdown+
What's Up with That +?
You might have noticed that the versioned directories here have a
\+
ap-
pended to them. This is a custom identifier that the Raspberry Pi Founda-
tion uses for their kernel builds, mostly to prevent conflicts with custom
kernel builds (which by default, do not contain a custom identifier).
The prebuilt core Linux kernel images will be looking for their modules in
these exact directory names (including the +), so do not rename them. If
there is an existing directory with the same name, it is reasonably safe to
overwrite it (assuming that you have also copied the matching kernel image
file from the same firmware checkout), but you can always rename the di-
rectory to act as a backup.
Just be aware that even if you boot the older kernel image via
kernel=
in
config.txt
, it will not know how to look in the renamed modules directory
and will try to load its modules from the original versioned directory.
The
3.6.10+
directory contains the modules that are built for
kernel.img
, while the
33.6.10-cutdown+
directory contains the modules that are built for
kernel_cut
down.img
. Makes sense, right? If you have copied
kernel_cutdown.img
into the boot
partition of your SD card, you will want the corresponding modules, but if you have
copied only
kernel.img
, you can leave them alone. It will not hurt anything to also copy
the cutdown kernel modules, but it will eat up about 15 MB more on your SD card.
For the prebuilt kernel, this will copy the proper modules:
$ cd ~/raspi/firmware/modules
$ su -c 'cp -a 3.6.10+ /mnt/raspi-root/lib/modules/'
From here on out, you will need to complete the same post-installation tasks that you
would do for a kernel installed from source, as described in
“Post-Installation Tasks”
on page 87
.
Merging Raspberry Pi Changes into Upstream
Linux Kernel Source
At some point, ideally, the Raspberry Pi Foundation will be able to merge all
of its Raspberry Pi (and BCM2835 system-on-chip) changes into the up-
stream Linux kernel source. This will mean that it is no longer necessary to
