I recently acquired an APU1D4 online and decided to try out OPNsense on it. This is a simple guide for installing OPNsense15.1.5 on an PC Engines APU1D4 using a USB drive, over a serial connection from an Ubuntu-based system.

Prepare the media¶

This phase is done on the Ubuntu-based workstation.

• Download the serial amd64 OPNsense image and extract it:
  

  cd ~/Downloads
  wget http://downloads.sourceforge.net/project/opnsense/15.1.5/OPNsense-15.1.5-memstick-serial-amd64.img.bz2
  tar xjf OPNsense-15.1.5-memstick-serial-amd64.img.bz2
  

• Write the OPNsense image to a spare USB drive:
  

  sudo dd if=OPNsense-15.1.5-memstick-serial-amd64.img
  sudo sync
  

• Install screen
  

  sudo apt-get install screen
  

• Now connect a NULL modem serial cable from COM1 on the Ubuntu-based workstation to COM1 on the APU1D4.

• Unplug the USB drive from the Ubuntu-based workstation and plug it into APU1D4.

• Open a terminal and run screen on COM1:
  

  sudo screen /dev/ttyS0 115200
  

Boot The APU1D4¶

• Plug the power to the APU1D4

• Quickly press [F10]
  • Select 1. USB MSC Drive

• Press 2 Boot to Single-User mode

Securely Erase Drive¶

The APU1D4 I bought came with an 80GB SSD. Just to be on the safe side I zero the hard drives of all new devices entering into my production environment.

• Erase SSD:
  

  dd if=/dev/zero of=/dev/ada0
  

  
  WARNING: Make sure that ada0 is the correct drive. Drive information in dmesg:
  

  dmesg | grep 'ada'
  

• Reboot the APU1D4
  

  reboot
  

Install OPNsense¶

• Quickly press [F10]
  • Select 1. USB MSC Drive

• Then select Accept Settings

• And select Quick/Easy Install then OK

• When the installation finishes select Reboot

• Remove the USB drive