RaspberryPi

Raspberry Pi

With the release of the Raspberry Pi 2 Model B and its ARMv7-based BCM2709 processor, it is now possible to run Ubuntu directly on the Raspberry Pi.

Note that the information on this page currently only applies to the Raspberry Pi 2 and 3, not the original Raspberry Pi. The Raspberry Pi 3 does not (yet) work with official Ubuntu images out of the box, but unofficial images are available.

Snappy Ubuntu Core

Snappy Ubuntu Core is a new rendition of Ubuntu with transactional updates - a minimal server image with the same libraries as today’s Ubuntu, but applications are provided through a simpler mechanism. Images are available for the Raspberry Pi 2 and 3.

Ubuntu 16.04 LTS 'classic'

These are not Ubuntu Core images, but the 'classic' deb based image.

Download

Note: The Pi 2 image is an updated Ubuntu 16.04.2 LTS classic image. The Pi 3 is an Ubuntu 16.04 LTS classic image.

Login username is "ubuntu", password is "ubuntu". You will be asked to change the password on first login.

Installation

Installation is the same as other Raspberry Pi images; a generic installation guide from raspberrypi.org is available here.

For example:

xzcat ubuntu.img.xz | sudo dd bs=4M of=/dev/mmcblk0

Or using ddrescue (must decompress the image first):

unxz ubuntu.img.xz
sudo ddrescue -D -d --force ubuntu.img /dev/mmcblk0

Optional PPAs

While the official image includes compatible firmware, bootloader and kernel, there are a few packages available in an unofficial PPA (ppa:ubuntu-raspi2/ppa) which are useful on the Raspberry Pi, including:

  • libraspberrypi-bin - VideoCore utilities from https://github.com/raspberrypi/userland such as vcgencmd, raspistill, etc.

  • libraspberrypi-bin-nonfree - Binary VideoCore utilities not provided in the open source userland repository, currently vcdbg and edidparser.

  • xserver-xorg-video-fbturbo - An accelerated x.org video driver, though this is limited to hardware accelerated window moving/scrolling on the Raspberry Pi.

  • hello-dkms - Not strictly to do with the Raspberry Pi, but a small example DKMS project to test building kernel DKMS modules.

To install:

sudo add-apt-repository ppa:ubuntu-raspi2/ppa
sudo apt-get update

Further Raspberry Pi packages can be found in the Ubuntu Pi Flavour Maker PPA.

Desktop

This is a small ubuntu-server image. If you want a full desktop, go ahead and do so:

$ sudo apt-get install xubuntu-desktop  # or
$ sudo apt-get install lubuntu-desktop  # or
$ sudo apt-get install kubuntu-desktop  # etc

Ubuntu (Unity) and Ubuntu-GNOME just display a blank screen, presumably because they require 3D compositing. Kubuntu works but is slow unless you turn off desktop effects under System Settings. Xubuntu and Lubuntu work fine out of the box.

Tasks can be installed and removed with Tasksel.

Accelerated X driver

An accelerated x.org video driver is available (fbturbo), though this is limited to hardware accelerated window moving/scrolling on the Raspberry Pi. Install the optional PPA above, then:

$ sudo apt-get install xserver-xorg-video-fbturbo

Then add this to /etc/X11/xorg.conf (create if it doesn't already exist):

Section "Device"
    Identifier "Raspberry Pi FBDEV"
    Driver "fbturbo"
    Option "fbdev" "/dev/fb0"
    Option "SwapbuffersWait" "true"
EndSection

VideoCore

As with Raspbian, VideoCore packages are available. Install the optional PPA above, then:

$ sudo apt-get install libraspberrypi-bin libraspberrypi-dev

However, since these packages are compiled from source during build, the files are installed in their "proper" locations in /usr. Some third-party scripts may expect e.g. /opt/vc/bin/vcgencmd; if so, this hack should do it:

$ sudo ln -s /usr /opt/vc

(Raspbian packages use precompiled repositories during build, which install in /opt/vc.) vcdbg and edidparser are not part of the open source package and must be installed separately:

$ sudo apt-get install libraspberrypi-bin-nonfree

Booting the official Pi 2 image on the Pi 3

The official Ubuntu images use u-boot as the bootloader. The u-boot binary built for the Pi 2 does not work on the Pi 3. This is why there are separate images for the Pi 2 and Pi 3.

However, the Raspberry Pi has its own built in bootloader. This can be used with a few changes to the config.txt file on the system-boot partition:

kernel=vmlinuz
initramfs initrd.img followkernel
#device_tree_address=0x02000000

Note the change to the kernel line, the addition of the initramfs line, and the commenting out (#) of the device_tree_address line.

All that remains is to copy bcm2710-rpi-3-b.dtb (plus the overlay folder if needed) from /lib/firmware/4.4.0-1065-raspi2/device-tree to the system-boot partition.

Once booted, you'll need to either uninstall the flash-kernel package, or upgrade the flash-kernel and u-boot packages from ppa:ubuntu-raspi2/ppa-rpi3.

If you've chosen to uninstall the flash-kernel package then you'll need to manually copy across the kernel and initrd files when you install a new kernel or update the initramfs. For example (note, the system-boot partition is mounted at /boot/firmware):

sudo cp /boot/vmlinuz /boot/firmware/
sudo cp /boot/initrd.img /boot/firmware/

The latest Pi 3 wifi firmware can be found here.

USB booting

The Raspberry Pi 3 (and Pi 2 v1.2 with the same BCM2837 SoC as the Pi3) is capable of booting from a USB drive. To do this you'll first need to program USB boot mode.

You must have bootloader files (confusingly referred to as the firmware on the Raspberry Pi) from after April 2017. So grab the latest bootcode.bin, fixup.dat and start.elf files from the GitHub repository and copy them to your system-boot partition.

Edit the cmdline.txt file

sudo nano /boot/firmware/cmdline.txt

and change root=/dev/mmcblk0p2 to root=LABEL=cloudimg-rootfs

If you are using a lot of drives then you may wish to switch to using the UUID of the partition.

Cross-upgrading 14.04 to 16.04

You can upgrade an old unofficial 14.04 installation to the official 16.04 installation, though it takes a number of additional steps.

Note that Ubuntu's setup uses u-boot as an intermediary bootloader, which is different from the previous system of the RPI2 booting the kernel directly. This will be reflected in the upgrade procedure.

Warning /!\ Once you begin this procedure, if you reboot the installation without completing the entire upgrade procedure, you will be left with an unbootable system. Warning /!\

First, remove a number of PPA packages which are obsoleted / incompatible with the 16.04.

apt-get --purge remove rpi2-ubuntu-errata raspberrypi-bootloader-nokernel \
  linux-image-rpi2 flash-kernel

Back up and remove the apt PPA configuration and module blacklists (the latter will be provided directly by the 4.4.0 kernel package).

mkdir -p /root/xenial-upgrade
tar zcvf /root/xenial-upgrade/etc.tar.gz \
  /etc/modprobe.d/rpi2.conf \
  /lib/modules-load.d/rpi2.conf \
  /etc/apt/preferences.d/rpi2-ppa \
  /etc/apt/sources.list.d/fo0bar-rpi2* \
  /etc/apt/trusted.gpg.d/fo0bar-rpi2*
rm -f \
  /etc/modprobe.d/rpi2.conf \
  /lib/modules-load.d/rpi2.conf \
  /etc/apt/preferences.d/rpi2-ppa \
  /etc/apt/sources.list.d/fo0bar-rpi2* \
  /etc/apt/trusted.gpg.d/fo0bar-rpi2*

Back up and remove the contents of /boot/firmware, which will be recreated.

tar zcvf /root/xenial-upgrade/firmware.tar.gz /boot/firmware/*
rm -rf /boot/firmware/*

Update apt sources without the old PPA configuration.

apt-get update

Run do-release-upgrade as normal. When asked to reboot at the end, do not, and select "n" instead.

do-release-upgrade -d
# -d will be unneeded once 16.04.1 is released

Install new firmware, u-boot and 4.4.0 kernel metapackages.

apt-get install u-boot-rpi u-boot-tools linux-raspi2 linux-firmware-raspi2 \
  linux-firmware flash-kernel

Install the RPI2 DT-compatible u-boot image.

apt-get install binutils  # for "strings"
wget -O /tmp/mkknlimg https://raw.githubusercontent.com/raspberrypi/linux/rpi-4.4.y/scripts/mkknlimg
chmod 0755 /tmp/mkknlimg 
/tmp/mkknlimg --dtok /usr/lib/u-boot/rpi_2/u-boot.bin /boot/firmware/uboot.bin

Install basic config.txt and cmdline.txt configurations. If your root device is not on the second SD partition (uncommon) or you have a more advanced configuration, recreate them here.

cat <<"EOM" >/boot/firmware/config.txt
kernel=uboot.bin
dtparam=i2c_arm=on
dtparam=spi=on
EOM

cat <<"EOM" >/boot/firmware/cmdline.txt
net.ifnames=0 dwc_otg.lpm_enable=0 console=ttyAMA0,115200 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline rootwait
EOM

Update the initrd and re-flash the kernel configuration.

update-initramfs -u
flash-kernel

Reboot!

reboot

Optionally add ppa:ubuntu-raspi2/ppa as described above.

Ubuntu 14.04 LTS

An Ubuntu 14.04 LTS (Trusty Tahr) image is available for the Raspberry Pi 2, which combines the released 14.04 distribution with a PPA containing kernels and firmware which work on the Raspberry Pi 2.

Warning /!\ This image, along with the one-off kernel it installs, is no longer maintained. Please use the 16.04 Xenial image instead. Warning /!\

Download

Usage

Root resize

There are no Raspbian-specific utilities included, specifically no automatic root resizer. However, it's not hard to do manually. Once booted:

$ sudo fdisk /dev/mmcblk0

Delete the second partition (d, 2), then re-create it using the defaults (n, p, 2, enter, enter), then write and exit (w). Reboot the system, then:

$ sudo resize2fs /dev/mmcblk0p2

Swap

There is no swap partition/file included. If you want swap, it's recommended you do:

$ sudo apt-get install dphys-swapfile

You should have a (resized) SD card at least 4GB, because by default it will want to create a ~2GB swapfile.

Wifi firmware

If you are using a wifi dongle, you will likely need to get the linux-firmware package:

$ sudo apt-get install linux-firmware

SSH server

If you would like to install an SSH server for remote access:

$ sudo apt-get install openssh-server

Serial console

To enable the serial console, change the /boot/cmdline.txt as follows:

dwc_otg.lpm_enable=0 console=ttyAMA0,115200 kgdboc=ttyAMA0,115200 console=tty1 root=/dev/mmcblk0p2 rootwait

and add a new file /etc/init/ttyAMA0.conf:

start on stopped rc or RUNLEVEL=[12345]
stop on runlevel [!12345]

respawn
exec /sbin/getty -L 115200 ttyAMA0 vt102

Kernel

The kernel used by the Raspberry Pi 2 port is an Ubuntu-style kernel package of an "rpi2" flavor, e.g. linux-image-3.18.0-20-rpi2. Currently it is comprised of the following functionality:

Ubuntu's 3.18 development is no longer active, as they moved on to 3.19 to be released with 15.04 vivid. However, mainline 3.18 was designated an LTS kernel release, and is still getting active security/stability updates. Because of this, 3.18 will likely remain the "supported" kernel of this port. (Again, this is an unofficial port and no support guarantee is implied.)

Building

  • The script used to build the images is available here.

If you want to build an image on your x86 Ubuntu host, install qemu-user-static package and edit the script to use "qemu-debootstrap --arch armhf" instead of "debootstrap":

qemu-debootstrap --arch armhf $RELEASE $R http://ports.ubuntu.com/

Ubuntu arm64/AArch64

'arm64' is the Debian port name for the 64-bit ARMv8 architecture, referred to as 'aarch64' in upstream toolchains (GNU triplet aarch64-linux-gnu), and some other distros.

BCM2837 is the chip used in the Raspberry Pi 3 and in later models of the Raspberry Pi 2. It packages a 64-bit quad-core ARM Cortex A53 (ARMv8) CPU with VideoCore IV GPU.

There is a config.txt entry to make the ARM start in 64-mode (otherwise 32-bit mode is used):

arm_control=0x200

(This will fail to boot unless you provide a kernel compiled for 64-bit mode)

64 bit versions of the linux-raspi2 kernels were introduced in Ubuntu 16.10 (Yakkety Yak).

The generic arm64 linux kernels can also be used with a suitable bootloader. For example, the Zesty mini.iso can be booted with a u-boot-UEFI-grub2 combination.

For those curious about what arm64 looks like (spoiler: it looks the same), a community built Lubuntu Live/Desktop iso for the Raspberry Pi 3 can be found online.

ARM/RaspberryPi (last edited 2017-10-10 17:42:40 by adamsmith)