Ok so I did a quick check: on my system (also flake), switching to a no-op takes 8s while doing the same kind of operation on the flake that will be deployed to the raspberry pi takes ~1.10mn, with 55s spend during the evaluation!! So it seems like something is really wrong with my raspberry pi setup, while I don’t think it contains anything crazy. Any idea how to troubleshot this? I tried nom but I don’t see much helpful operations there (it helps only during the compilation part), I’ll check the thread you mention, but it’s a bit confusing to see many methods that are a bit old, so if you have some recommandations to try that work with flake + remote builders that would be great. I also see that nix now has an official profiler A look at NixOS/Nixpkgs evaluation times over the years - #39 by purepani can I use it in this context?