=====PC Engines APU/APU2 - Debian 12, Bookworm=====

**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.


====Documentation sources====
  * [[https://www.pcengines.ch/apu.htm|PC Engines APU Board]]
  * [[https://www.pcengines.ch/apu2.htm|PC Engines APU2 Board]]
  * [[https://wiki.debian.org/DebianInstaller/CreateUSBMedia|Debian - Manually copying files to the USB stick]]

====Required hardware====
  * APU board
  * Power supply
  * Internet over Ethernet
  * Serial (via Serial<->USB adapter)
  * mSATA SSD

====Install Debian 12, Bookworm====
  * [[https://cdimage.debian.org/debian-cd/current/amd64/iso-cd/debian-12.1.0-amd64-netinst.iso|Download the amd64 netinst ISO]] (a DVD image for offline install might work, not tested)
  * [[https://deb.debian.org/debian/dists/bookworm/main/installer-amd64/current/images/hd-media/boot.img.gz|Download syslinux installer]]
  * Copy syslinux image to USB:<code>zcat boot.img.gz | sudo dd bs=4M iflag=fullblock of=/dev/sdX oflag=direct status=progress</code>
  * Re-insert and then mount the USB drive:<code>sudo mount /dev/sdX1 /mnt</code>
  * Configure a serial console, edit /mnt/syslinux.cfg and add the 'serial' line:<code># 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</code>
  * Copy the netinst ISO image to the USB drive:<code>cp debian-12.1.0-amd64-netinst.iso /mnt</code>
  * Unmount the USB drive:<code>umount /mnt</code>
  * Boot the APU board from the USB drive (APU Boot menu = F12, APU2 = F10):<code>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]
</code>
  * Press ''i'' and <TAB>
  * Then change the command into the following:<code>linux initrd=initrd.gz qfxpayload=text console=ttyS0,115200n8</code>
  * 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 \\ {{::screenshot_from_2023-09-20_22-11-21.png?nolink|}}
  * Press Ctrl-x to boot
  * Log in and edit /etc/default/grub:<code>GRUB_CMDLINE_LINUX="console=ttyS0,115200n8"</code>
  * Update grub:<code>update-grub</code>
  * Reboot
====Post-install====
===Firewall===
  * Configure default firewall<code>cp /usr/share/doc/nftables/examples/workstation.nft /etc/nftables.conf
vi /etc/nftables.conf  # accept port 22 for example
systemctl enable --now nftables
</code>

===APU2 LEDs===
Configure front LEDs to blink on network and disk activity.
  * Add ledtrig modules to ''/etc/modules''.<code>
cat >> /etc/modules <<EOF
ledtrig-default-on
ledtrig-netdev
ledtrig-heartbeat
EOF
</code>
  * Load the modules with ''modprobe''
  * Add settings to sysfs.conf:<code>
# 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</code>
  * Enable sysfs:<code>systemctl enable sysfsutils</code>
  * Reboot
===Watchdog===
  * Enable watchdog in BIOS, set timeout for example to 300 seconds.
  * Disable i2c_piix4 [[https://pcengines.github.io/apu2-documentation/theory-of-operation/]]<code>cat > /etc/modprobe.d/noi2c.conf <<EOF
# Disable i2c_piix4, see https://pcengines.github.io/apu2-documentation/theory-of-operation/
blacklist i2c_piix4
EOF</code>
  * Update initramfs.<code>update-initramfs -u</code>
  * Edit ''/etc/systemd/system.conf'' and enable watchdog.<code>RuntimeWatchdogSec=60</code>
  * Reboot
  * Test the watchdog by pausing the init process. It should reboot after the configured timeout.<code>apt install gdb
gdb -p 1</code>


{{tag>[hardware apu debian linux ]}}