SteamOS 3 proper will come out sometime after launch (and even then it may not work on your toaster).While Steam Deck is fully capable of dual-boot, the SteamOS installer that provides a dual-boot wizard isn't ready yet. This will ship alongside SteamOS 3 once it's complete.While Steam Deck is fully capable of dual-boot, the SteamOS installer that provides a dual-boot wizard isn't ready yet. This will ship alongside SteamOS 3 once it's complete.