Last modified at 11/2/2013 11:44 AM by Koen Zomers

Notice for pfSense 2.1+ users: These steps are no longer required with pfSense 2.1. PfSense 2.1 and onwards will be able to boot from an USB disk with just installing it using now option #3 from the first menu which dictates to boot using an USB device. From there on, the installation will take care that the booting from the USB disk can be done without having to change the boot loader yourself.

It is possible to install pfSense on an USB disk. I'm using an 2,5 inch USB boot disk in my pfSense firewall because its very energy efficient compared to a normal SATA disk. In order to install and run pfSense from an USB disk, follow these steps:

  1. Connect your USB disk and power on your system.
  2. Make sure the BIOS detects the USB disk. You have several options to check this. One of them being going into the BIOS setup and checking the initialized disks, another option being selecting the boot menu during the BIOS boot screen and checking if your USB disk is listed in the devices list.
  3. Insert the pfSense installation CD into the CD-Rom player of your system and let it boot from the CD.
  4. At the pfSense boot menu, make sure you choose option number 3: Boot pfSense using USB device instead of letting it boot with the default options after the timeout.

  5. Install pfSense as you normally would.
  6. To remove the manual requirement to use boot option 3 each time your pfSense system boots, once in the pfSense menu after the installation, use option 8 to go to the console.
  7. In the console type:

    vi /boot/loader.conf.local
  8. Press Insert on your keyboard and start typing the following text (watch for typos!):


  9. Once done, press Escape on your keyboard and enter:


    followed by pressing Enter
  10. Reboot pfSense using the following command. It should now default to boot with USB support.

    shutdown -r now