@ebi Heh, that's a tricky one!

So I would say that there's not really any *fundamental* difference between ARM/mobile and other systems, in that all the same benefits are still useful on those devices for all the same reasons.

What *is* different, however, is the typical hardware configuration of such devices - and I can see some issues there with the current state of Nix and NixOS.

Some things that come to mind:

- Nix is currently not exactly resource-efficient. It requires quite a bit of CPU and RAM to evaluate a system configuration, which is not great on many mobile devices, which are often specced lower.

- The atomic upgrade model is great, but also very space-hungry. Again, mobile devices are frequently not very generous on storage space, and this could cause issues, at least without a deduplicating filesystem.

- Nix is still heavily keyboard-oriented, and well, most such devices don't have a keyboard :) So it's probably *even more* important for there to be good management UIs on such devices. Less of a problem for embedded ARM stuff like routers.

I don't think that any of these issues are impossible to overcome, but there's definitely quite a bit of 'core work' left to make this viable outside of an experimental context.

That having been said, there *is* https://mobile.nixos.org/ as an ongoing project. I've also seen various efforts for running NixOS on eg. ARM routers, but I'm not sure what the status of any of them is.

Perhaps more interesting in the immediate term is using Nix as a build system for eg. Android images; and there's actually active work ongoing here! Robotnix can build customized AOSP systems, for example: https://github.com/danielfullmer/robotnix

Maybe other "off-device" approaches might be viable as well - if it doesn't need to run on the device itself, that'll at least eliminate the CPU/RAM constraints.

In summary: I think it would be really cool to run NixOS on mobile/ARM devices, but I think that in practical terms we're still quite a way away from it - further than for desktop/server usage.