Booting FreeBSD over USB


New Member

Messages: 2

Hello everyone, since i had lots of free time lately i decided to try FreeBSD 12 32bit for the first time.
Although installation has been very complicated and time consuming, ive managed to install it on my laptop.
Now here's the deal, i have enclosed my laptop HDD into external casing, you know the one that instead of using sata, it connects your HDD over USB?
Basically it wont boot FreeBSD now, i have tried every single option , it always gets stuck on this screen.
please help me fix this, thanks




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Messages: 43

Seems that you are trying to mount root from wrong devive. da0 is your USB device but you are trying to mount root from ada0, which is SATA device.


Active Member

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Messages: 177

And besides fixing /etc/fstab as mentioned by Argentum, you'll need to add the following line to /boot/loader.conf:


Well-Known Member

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Messages: 256

The text on the photo suggests typing "?" to list valid boot devices. lsdev should also work.



Reaction score: 6
Messages: 43

Great, how do i make it boot from da0 in the future?
You can try reading the manual: mount.conf()

  1. Create yourself a bootable media, USB stick for example. (you can use standard USB Install Image for that purpose);
  2. boot it up and mount your file systems from your USB device somewhere;
  3. fix /etc/fstab and /boot/loader.conf as described here ;
  4. try to boot your new (USB) device


Son of Beastie

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One way is to let it fail at mount root error (You might need to disable SATA in BIOS) and then enter your USB device.

The way I prefer is at the very end of the FreeBSD installation it allows you to drop to a post installation shell.
From there edit /etc/fstab to use da0.

Another way would be to label your USB stick and have /etc/fstab point to the label instead of USB stick.

Lastly you can boot up off the FreeBSD USB Memstick Installer use LiveCD mode and mount the installation and fix fstab.