2020-09-18 - This is a how to guide for updating the BIOS and installing Debian Buster on the PC Engines APU boards. This is a network based installation, connect internet via Ethernet.

• https://www.pcengines.ch/apu2.htm

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

• Download the latest BIOS for your version of the board here: https://pcengines.github.io/.
• Download the TinyCore image.
• Write image to USB flash drive.

  zcat apu2-tinycore6.4.img.gz | sudo dd of=/dev/sdX bs=1M conv=fsync status=progress

• Mount the USB flash drive.

  sudo mount /dev/sda1 /mnt

• Copy rom to flash:

  sudo cp apu2_v4.12.0.4.rom /mnt

• Unmount the flash drive and boot the APU board from it.

  sudo umount /mnt

• If you see a lot of messages like below, just ctrl-c:

  FAT partition not mounted yet, retrying since 3 s
  FAT partition not mounted yet, retrying since 6 s^C

• Flash the BIOS and reboot when finished:

  cd /media/SYSLINUX
  flashrom -p internal -w apu2_v4.12.0.4.rom
  
  reboot
  
  ...
  PC Engines apu2
  coreboot build 20202708
  BIOS version v4.12.0.4
  4080 MB ECC DRAM
  ...

• Download amd64 netinst ISO: https://cdimage.debian.org/debian-cd/current/amd64/iso-cd/debian-10.5.0-amd64-netinst.iso
• Copy image to USB drive:

  sudo dd if=debian-10.5.0-amd64-netinst.iso of=/dev/sdX bs=4k status=progress

• Unmount USB drive.
• Boot APU from USB.
• Press h and <ENTER>.
  
• Then enter the following 'install' command:

  #Press F2 through F10 for details, or ENTER to boot: 
  install vga=off console=ttyS0,115200n8

• Press <ENTER> to start install.
• During install, deselect any desktop environment and select the SSH server and standard system utilities.
• At first reboot, you'll get the following error:

  text is deprecated. Use set gfxpayload=vga=off before linux command instead.

• Reboot, and at the grub menu press e and remove the vga=off option. Press ctrl-x to boot.
• Then edit /etc/default/grub, remove vga=off and run update-grub.