Install Ubuntu 18.04 LTS on a PC Engines APU2 board.

If you're using an APU1 board, try the section Prepare a USB drive (optional) to create a prepared USB-drive first. Then boot from USB (press F12, during boot) and select Command-line install and proceed with the installation.

• dd Ubuntu server netinstall (mini.iso) to USB drive https://www.ubuntu.com/download/alternative-downloads, be sure to select the amd64 arch.
• Connect the USB drive to the APU2 board and boot from USB, press F10 at boot.
• Select Install, then TAB.
• Change kernel options to linux initrd=initrd.gz console=ttyS0,115200
• When asked to unmount mounted partitions choose Yes.
• Install options as you like.
• Reboot after install.

• At the grub menu, press 'e'.
• Scroll to the line starting with linux and add:

  console=ttyS0,115200n8

• Then press 'ctrl-x' to boot.
• You can now log in with your user account.
• Modify grub:

  sudo vi /etc/default/grub
  GRUB_CMDLINE_LINUX="console=ttyS0,115200n8"
  
  sudo update-grub

• Reboot to test the update grub configuration.

• Edit /etc/netplan/01-netcfg.yaml

  # This file describes the network interfaces available on your system
  # For more information, see netplan(5).
  network:
    version: 2
    renderer: networkd
    ethernets:
      enp1s0:
        addresses:
          - 10.10.10.2/24
        gateway4: 10.10.10.1
        nameservers:
            search: [mydomain, otherdomain]
            addresses: [10.10.10.1, 1.1.1.1]

• Apply config:

  netplan apply

• Install and start openssh:

  apt install openssh-server

• Enable firewall:

  ufw allow ssh
  ufw enable

• Multi-user target (not graphical):

  sudo systemctl set-default multi-user.target

• Configure timezone:

  dpkg-reconfigure tzdata

• Configure locale:

  dpkg-reconfigure locales

It seems the sp5100_tco module is blacklisted by default in /lib/modprobe.d. We need to override that and blacklist some conflicting modules.

• Blacklist conflicting modules:

  cat >> /etc/modprobe.d/blacklist-i2c-ccp.conf <<EOF
  blacklist i2c_piix4
  blacklist ccp
  EOF

• Update the initramfs:

  update-initramfs -u

• Install watchdog:

  apt install watchdog

• Add module to config:

  vi /etc/default/watchdog 
  # Load module before starting watchdog
  watchdog_module="sp5100_tco"

• Edit /etc/watchdog.conf:

  watchdog-device = /dev/watchdog

• Reboot to test:

  dmesg | grep sp5100_tco

• Kill watchdog, it should restart your system after some time:

  pkill -9 watchdog
  # if wd_keepalive is started, also kill that
  pkill -9 wd_keepalive

• Install beep:

  apt install beep

• Comment or remove pcspkr from /etc/modprobe.d/blacklist.conf.

• For APU1 see: https://github.com/trick77/apu-led-button

• ACPId is already installed and should be working.
  • Short press: shutdown
  • Long press: hard power off
  • When powered off, short press, will power on.
• You can add a beep, just before shutdown.

  cat >> /etc/systemd/system/beeponshut.service <<EOF
  [Unit]
  Description=beep
  
  [Service]
  Type=oneshot
  RemainAfterExit=true
  ExecStart=/bin/true
  ExecStop=/usr/bin/beep -f500 -l50 -r3 -n -f1 -l50 -n -f400
  
  [Install]
  WantedBy=multi-user.target
  EOF
  
  systemctl daemon-reload
  systemctl enable beeponshut

• Install required packages:

  apt install xorriso isolinux

• Download the latest Ubuntu server net install mini.iso for amd64 architecture.
• Extract downloaded ISO and copy the files to a temporary location:

  sudo mkdir /mnt/iso
  sudo mount -o loop ~/Downloads/mini.iso /mnt/iso
  cd /mnt
  tar -cvf - iso | (cd /var/tmp/ && tar -xf - )
  cd /var/tmp/iso

• Modify isolinux.cfg

  serial 0 115200
  console 0
  path
  include menu.cfg
  default vesamenu.c32
  prompt 0
  timeout 0

• Modify cli / Command-line install: txt.cfg

  #From:
  append tasks=standard pkgsel/language-pack-patterns= pkgsel/install-language-support=false vga=788 initrd=initrd.gz --- quiet 
  
  #To:
  append tasks=standard pkgsel/language-pack-patterns= pkgsel/install-language-support=false vga=off initrd=initrd.gz console=ttyS0,115200n8 ---
  

• Create a new ISO file:

  #Fedora host:
  xorriso -as mkisofs -R -J -V "Ubuntu-Server 18.04 LTS amd64" \
  -o ~/file.iso -b isolinux.bin -c boot.cat -no-emul-boot \
  -boot-load-size 4 -boot-info-table \
  -isohybrid-mbr /usr/share/syslinux/isohdpfx.bin .
  
  #Ubuntu host:
  xorriso -as mkisofs -R -J -V "Ubuntu-Server 18.04 LTS amd64" \
  -o ~/file.iso -b isolinux.bin -c boot.cat -no-emul-boot \
  -boot-load-size 4 -boot-info-table \
  -isohybrid-mbr /usr/lib/ISOLINUX/isohdpfx.bin .
  
  
  

• Write the new image to the USB drive:

  sudo dd if=~/file.iso of=/dev/sdX bs=4M