"<a href=""https://www.youtube.com/watch?v=9mej3QXMyMk&amp;t=0m40s"">0:40</a> ETA Prime didn't use Windows for the Steam Deck eGPU experiment because Steam OS doesn't play nice with external GPUs", but because it's currently impossible or at least very difficult to install SteamOS 3.0 on an SD card, and the M.2 slot is of course taken up by the external GPU adaptor.,(reply>), And I'm really shocked by this / starting to wonder at what point this becomes a GPL violation that the source code of SteamOS 3 is apparently... nowhere.