SiO2 is a tool to build pre-configured OpenBSD iso.


You can build a SiO2 iso with these commands :

tar xvzf archive.tar.gz
cd SiO2*
make download
sudo make iso

As dependencies, only “curl” and “genisoimage” are required.

A file CustomOBSD.iso will be created.


The install process is the same as OpenBSD one. You juste have to select the “site-*.tgz” set. A configuration is make at first boot after install. .


Edit the file obdiso.conf to customize the openbsd version, packages to install, mirror to use to download iso…

You can get the build environment with

make prepare

The configuration can be personnalized by filling up a site/ directory.

Reproduce in this directory the file tree you want on your freshly installed system. As example :


You can put in the site/ directory two scripts (both must have 755 permission):

  • site/ : every command in this script will be run just after the installation in the new system (chrooted)
  • site/etc/rc.firsttime : this script will be run at the first boot of the fresly installed system

Else, see README