I've recovered some systems I b0rked by dding from a healthy system or a livedisk to a machine I updated incorrectly, I could have tried just copying from the disk fine and figured it out I'm sure, but I didn't want to open another rabbit hole with the SteamOS update and config. SteamOS has duplicate /, /var, and /boot partitions, and I assume there's some part of the install configuration that sets the active and inactive sets.

Really I was just after testing/listing included bt drivers on some specific hardware for some wonky controllers I have, installation was a secondary thought.