After a while of no updates to the actual ISO download of HoloISO, the creator of this SteamOS-like Linux distribution has announced the original is now dead. As it's being replaced by the newer immutable HoloISO.
“We’re hoping soon, though, it is very high on our list, and we want to make SteamOS more widely available. We’ll probably start with making it more available to other handhelds with a similar gamepad style controller. And then further beyond that, to more arbitrary devices. I think that the biggest thing is just, you know, driver support and making sure that it can work on whatever PC it happens to land on. Because right now, it’s very, very tuned for Steam Deck.”
“We’re hoping soon, though, it is very high on our list, and we want to make SteamOS more widely available. We’ll probably start with making it more available to other handhelds with a similar gamepad style controller. And then further beyond that, to more arbitrary devices. I think that the biggest thing is just, you know, driver support and making sure that it can work on whatever PC it happens to land on. Because right now, it’s very, very tuned for Steam Deck.”
https://www.pcgamer.com/steamos-on-handheld-pcs/