Flashing a Robot

How to install a new operating system on a robot
Updated 8 Sept 2021

Flashing a Robot

To install Arch Linux (our OS of choice) on to a robot perform the following instructions. Make sure you know the robot number for this NUC before beginning.

  1. Download the latest Arch Linux LiveUSB image and burn it on to a USB thumb drive using the following instructions

    • Find the USB drive in your system. This will vary from one system to another and choosing the wrong drive will cause irreversible data loss.
      • Use sudo fdisk -l, or the Disks GUI program to find your USB drive. It will probably be /dev/sdX, where X is a letter of the alphabet.
    • Burn the Arch Linux ISO you just downloaded to the USB drive (in this example we are using /dev/sdb)
    • sudo dd bs=4M if=~/Downloads/archlinux-2019.11.01-x86_64.iso of=/dev/sdb status=progress oflag=sync
  2. If you are using a brand new NUC, Boot into the BIOS on the NUC

    • Turn the NUC on and hold down the F2 button
    • Intel Visual BIOS should appear
    • Navigate to "Advanced" menu
    • Navigate to "Power" then set "After Power Failure" to "Power On"
      BIOS Power Menu
      BIOS Power Menu
    • Navigate to "Boot" and then "Boot Configuration"
      • Ensure "Boot USB Devices First" is enabled in "UEFI Boot"
      • Ensure "USB" is enabled in "Boot Devices"
        BIOS Boot Configuration Menu
        BIOS Boot Configuration Menu
    • Navigate to "Secure Boot" and disable "Secure Boot"
      BIOS Secure Boot Menu
      BIOS Secure Boot Menu
    • Press F10 to save settings and exit and ensure you USB drive is plugged in
  3. If you are not using a brand new NUC, ensure your USB drive is plugged in and turn the NUC on

  4. Once the system has booted into the LiveUSB environment on the robot, ensure the robot has an active network connection

    • LiveUSB Environment
      LiveUSB Environment
    • Run ip addr and look for a inet line that has a valid IP address on it. If you can't see one you don't have a network connection. Alternatively, run ping -c 3 google.com and look for a response time.

      Internet connection
      Internet connection
      No internet connection
      No internet connection
    • If you have no connection and need to set up the WiFi interface, see below.

  5. Download the installation script https://git.io/JeWaF and make sure the script is executable

    • curl -L https://git.io/JeWaF -o ./arch_install.sh
      chmod +x ./arch_install.sh
    • The installation script is located in the NUbots repository at doc/ArchInstall/arch_install.sh
  6. Execute the script and follow the instructions

    • ./arch_install.sh

The installation script will end by downloading a secondary script and providing you with a command that you must run

ROBOT_NUMBER=<N> arch-chroot /mnt ./arch-chroot_install.sh

Substitute <N> with the number of the robot that you are building. This will influence the IP address of the robot as well as the robots' hostname.

The secondary script assumes that the network interfaces are named eth0 for ethernet and wlan0 for WiFi. If you know this is not the case then execute the script as follows

ROBOT_NUMBER=<N> \
ETHERNET_INTERFACE=IF_NAME \
WIFI_INTERFACE=IF_NAME \
arch-chroot /mnt ./arch-chroot_install.sh

Finally, once that script has finished, you must run one more command.

/mnt/arch-post_install.sh

This command will end by rebooting the robot. When this happens be sure to remove the USB installation drive from robot so that you may boot into the new system.

The final two scripts can be found at doc/ArchInstall/arch-chroot_install.sh and doc/ArchInstall/arch-post_install.sh

Testing the new robot

Once installation is complete and you have booted into your shiny new OS, you should perform a couple of simple tests to ensure everything is operational.

First, login to system

Login
Login

Now check for a network connection, the same as we did before. If ip addr indicates that there is no connection then it is likely that the secondary installation script made the wrong guess about the name of the network interfaces. Inspect the output from ip link and make note of the ethernet and wifi interface names.

It is possible that ip addr will show a valid IP address for bond0, but ping -c 3 google.com and ping -c 3 8.8.8.8 will indicate that there is no network connection.

If there is no connection, then the following files need to be modified (using either sudo nano or sudo vim)

  • /etc/systemd/network/20-eth0.network
  • /etc/systemd/network/30-wlan0.network
  • /etc/systemd/network/99-eth0.network
  • /etc/systemd/network/99-wlan0.network
  • /etc/wpa_supplicant/wpa_supplicant-wlan0.conf

These 5 files need to be both renamed (replacing eth0 or wlan0 with the new interface name) and the contents of the files need to be edited, specifically the line that says Name=eth0 or Name=wlan0.

Next, correct the wpa_supplicant service by running

sudo systemctl disable wpa_supplicant@wlan0
sudo systemctl enable wpa_supplicant@new_interface

Be sure to replace new_interface with the name of the WiFi interface.

Once these files have been fixed, reboot by typing sudo systemctl reboot and then login again. Hopefully, ip addr indicates that there is an active network connection (on bond0) and ping -c 3 google.com also indicates an active connection.

Manually setting up a WiFi connection on the robot

To set up the WiFi interface you first need to know the name of the interface. To find this, run

ip link
Known network interfaces
Known network interfaces

and look for an interface starting with wl. On our robots it is usually wlan0.

The rest of these instructions assume a network using WPA2 (like the network used in the NUbots lab).

  1. Make sure the wpa_supplicant configuration directory exists

    • mkdir -p /etc/wpa_supplicant
  2. Setup the network configuration

    • wpa_passphrase <Network SSID> <Network Passphrase> > /etc/wpa_supplicant/wpa_supplicant-<WiFi Interface>.conf
    • Be sure to replace <Network SSID> with the SSID of the wireless network to connect to (either epsilon-x or epsilon-z in the lab), <Network Passphrase> with the password for the network (ask someone for the lab password if you don't know it), and <WiFi Interface> with the name of the interface found earlier.
  3. Now start all of the necessary services

    • systemctl start dhcpcd.service
      systemctl start wpa_supplicant.service
      systemctl start wpa_supplicant@<Wifi Interface>.service
    • Be sure to replace <WiFi Interface> with the name of the interface found earlier.
    • Wait a handful of seconds and run ip addr to check that the WiFi interface has an IP address
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