2023-09-14 - This is a manual install guide for installing Debian 12 Bookworm on the PC Engines APU/APU2 board. It is a network based installation, you'll need to have a working internet connection using one of the Ethernet ports.

• PC Engines APU Board
• PC Engines APU2 Board
• Debian - Manually copying files to the USB stick

• APU board
• Power supply
• Internet over Ethernet
• Serial (via Serial↔USB adapter)
• mSATA SSD

• Download the amd64 netinst ISO (a DVD image for offline install might work, not tested)
• Download syslinux installer
• Copy syslinux image to USB:

  zcat boot.img.gz | sudo dd bs=4M iflag=fullblock of=/dev/sdX oflag=direct status=progress

• Re-insert and then mount the USB drive:

  sudo mount /dev/sdX1 /mnt

• Configure a serial console, edit /mnt/syslinux.cfg and add the 'serial' line:

  # D-I config version 2.0
  # search path for the c32 support libraries (libcom32, libutil etc.)
  path 
  prompt 0
  timeout 0
  serial 0 115200
  include menu.cfg
  default vesamenu.c32

• Copy the netinst ISO image to the USB drive:

  cp debian-12.1.0-amd64-netinst.iso /mnt

• Unmount the USB drive:

  umount /mnt

• Boot the APU board from the USB drive (APU Boot menu = F12, APU2 = F10):

  Build date: Apr  5 2014
  System memory size: 4592 MB
  
  Press F12 for boot menu.
  
  Select boot device:
  
  1. AHCI/0: KINGSTON SMS200S330G ATA-8 Hard-Disk (28626 MiBytes
  2. USB MSC Drive SanDisk Ultra 1.00
  3. iPXE (PCI 00:00.0)
  4. Payload [setup]
  5. Payload [memtest]

• Press i and <TAB>
• Then change the command into the following:

  linux initrd=initrd.gz qfxpayload=text console=ttyS0,115200n8

• Press <ENTER> to start install.
• During installation, deselect any desktop environment and select the SSH server and standard system utilities.

• If the console setting is not saved during next boot, i.e. no output to serial console, follow the next steps.
• Edit the grub entry (press e in grub menu) and add console=ttyS0,115200n8 to the linux command-line parameters
  
• Press Ctrl-x to boot
• Log in and edit /etc/default/grub:

  GRUB_CMDLINE_LINUX="console=ttyS0,115200n8"

• Update grub:

  update-grub

• Reboot

• Configure default firewall

  cp /usr/share/doc/nftables/examples/workstation.nft /etc/nftables.conf
  vi /etc/nftables.conf  # accept port 22 for example
  systemctl enable --now nftables

Configure front LEDs to blink on network and disk activity.

• Add ledtrig modules to /etc/modules.

  cat >> /etc/modules <<EOF
  ledtrig-default-on
  ledtrig-netdev
  ledtrig-heartbeat
  EOF

• Load the modules with modprobe
• Add settings to sysfs.conf:

  # Install sysfs utils
  apt install sysfsutils
  
  # Append config to /etc/sysfs.conf
  cat >> /etc/sysfs.conf <<EOF
  class/leds/apu2:green:led1/brightness = 1
  class/leds/apu2:green:led2/trigger = disk-activity
  class/leds/apu2:green:led3/trigger = netdev
  class/leds/apu2:green:led3/rx = 1
  class/leds/apu2:green:led3/tx = 1
  class/leds/apu2:green:led3/device_name = enp1s0
  EOF

• Enable sysfs:

  systemctl enable sysfsutils

• Reboot

• Enable watchdog in BIOS, set timeout for example to 300 seconds.
• Disable i2c_piix4 https://pcengines.github.io/apu2-documentation/theory-of-operation/

  cat > /etc/modprobe.d/noi2c.conf <<EOF
  # Disable i2c_piix4, see https://pcengines.github.io/apu2-documentation/theory-of-operation/
  blacklist i2c_piix4
  EOF

• Update initramfs.

  update-initramfs -u

• Edit /etc/systemd/system.conf and enable watchdog.

  RuntimeWatchdogSec=60

• Reboot
• Test the watchdog by pausing the init process. It should reboot after the configured timeout.

  apt install gdb
  gdb -p 1