I have successfully installed FreeBSD 7.2Release (i386) from a USB flash drive. It involves a little more work than installing from CD/DVD but the convenience of having it on a USB flash drive makes it worth it. I created a single bootable slice with only a "/" partition. Then I used tar to copy everything from the FreeBSD DVD ISO image to the flash drive. I know cpio is a potentially better way to do it, but I wanted to keep this description simple. The problem that people have posted on before is that they did not know how to mount an "existing filesystem" so "sysinstall" can find the files. Well, this is fairly simple to do as it turns out. During the drive selection, you see the IDE drive you want to install to, and the USB flash drive. Select both , but only partition the destination drive. When you create the mount points for the new drive, you will see an entry for the existing USB flash drive filesystem with no mount point of its own, yet. Select that entry and hit "m" to set the mount point. I set mine to /mnt, of course after I created the "/" entry on the destination drive. Now you have the mount point, and you can tell sysinstall to mount it as an existing file system. I put together a crude first approximation of the process at http://www.pa.msu.edu/people/tigner/BootUSB.html. I will try to clean it up when I get a chance, or feel free to improve on it yourself .