Hardware Reference
In-Depth Information
• It does require you to run the script from within the running Linux environment.
Make sure that the time is set properly within the environment, or you might get
script failures relating to clock drift.
• The script does not let you perform fine-grained update operations (e.g., just
update the firmware). It is an all-or-nothing experience.
• The script assumes that the VideoCore files are located under
/opt/vc
. Some
Raspberry Pi Linux distributions (such as Pidora) place the VideoCore files in a
different location or include them in the system library directories, so this script
will not work well for them.
The
rpi-update
script does not use the official GitHub repository for prebuilt files be-
cause of the size of that repository. Instead, Hexxeh keeps a copy of those files in a
separate GitHub repository with a different filesystem layout.
While this separate repository seems to be manually synced with the official reposi-
tory on a regular basis, keep in mind that it is possible that you will not be getting the
absolute latest available revisions of these files. Sometimes, that's how it goes when
you try to take shortcuts.
Emulate the Pi
HACK 26
Whether you're travelling without your Pi, need to test something in a
hurry, or your kids have taken over the Pi while you weren't looking, it can
sometimes be convenient to emulate it on another machine. QEMU can
help.
QEMU (short for
Quick EMUlator
) is an open source, hosted hypervisor. That means
that you can use it to run a Linux distro that was made for your Raspberry Pi (which
uses ARM hardware) on your usual computer (an x86 laptop, for example).
It has two modes. The first is user-mode emulation, which lets you run single programs
that weren't compiled for your machine. But this hack focuses on QEMU's full-system
emulation, which lets you emulate an entire computer—in this case, a Raspberry Pi.
First install QEMU, by running this command on Fedora:
$ su -c 'yum install qemu'
Or, you can run this on Debian/Ubuntu:
$ su -c 'apt-get qemu-system-arm'
qemu
. You can also
compile your own kernel
.
