diff --git a/.envrc b/.envrc
index 1d953f4..8392d15 100644
--- a/.envrc
+++ b/.envrc
@@ -1 +1 @@
-use nix
+use flake
\ No newline at end of file
diff --git a/default.nix b/default.nix
index 1950006..f01ab85 100644
--- a/default.nix
+++ b/default.nix
@@ -9,28 +9,26 @@ let
   inherit (pkgs) lib;
   inherit (lib.filesystem) listFilesRecursive;
   inherit (lib.strings) hasSuffix;
-  inherit (lib.attrsets) genAttrs;
 
-  nixosSystem = import (sources.nixpkgs + "/nixos/lib/eval-config.nix");
   mkSystem =
     hostname:
-    nixosSystem {
-      system = null;
+    import (src.nixpkgs + "/nixos/lib/eval-config.nix") {
       specialArgs = {
         inherit sources;
         self = ./.;
       };
       modules = [
+        # This is used to pre-emptively set the hostPlatform for nixpkgs.
+        # Also, we set the system hostname here.
         { networking.hostName = hostname; }
+        ./hosts/common.nix
         ./hosts/${hostname}
       ]
       ++ ((listFilesRecursive ./modules) |> filter (hasSuffix ".mod.nix"));
     };
-
-  hosts = [
-    "temperance"
-    "hermit"
-    "tower"
-  ];
 in
-genAttrs hosts mkSystem
+{
+  temperance = mkSystem "temperance";
+  hermit = mkSystem "hermit";
+  tower = mkSystem "tower";
+}
diff --git a/docs/dualboot.md b/docs/dualboot.md
new file mode 100644
index 0000000..e1571e5
--- /dev/null
+++ b/docs/dualboot.md
@@ -0,0 +1,55 @@
+# Dualbooting NixOS and FreeBSD
+
+Out of curiosity, I decided to dual-boot NixOS and FreeBSD on my laptop, sharing
+one disk. I document the process here for future reference:
+
+## Linux install
+
+First, flash a stick with NixOS, then boot into it, wipe your disk, create two
+partitions, one being boot, the other your main NixOS partition. Then, follow
+these commands:
+
+```bash
+sudo su
+
+cryptsetup luksFormat /dev/diskname/partition
+
+cryptsetup open /dev/diskname/partition crypt
+
+mkfs.btrfs -L nixos /dev/mapper/crypt
+
+mount /dev/mapper/crypt /mnt
+
+btrfs create subvolume /mnt/nix
+btrfs create subvolume /mnt/home
+btrfs create subvolume /mnt/persist
+
+mkdir /mnt/boot
+mount /dev/partition # boot partition
+```
+
+Then, copy [my nixos flake](https://github.com/bloxx12/nichts) to `/mnt`, you
+can remove it from there later on.
+
+```bash
+git clone https://github.com/bloxx12/nichts /mnt
+```
+
+In there, change the file system uuids to the correct ones, you can see them
+using
+
+```bash
+sudo blkid
+```
+
+Then, install NixOS itself:
+
+```bash
+nixos-install --impure --flake /mnt/nichts#<hostname> -j 1 --cores 2
+```
+
+Wait for that to finish, then reboot.
+
+If your system works, great! if not, redo from the beginning.
+
+After that, set up FreeBSD the following way:
diff --git a/hosts/common.nix b/hosts/common.nix
new file mode 100644
index 0000000..0405615
--- /dev/null
+++ b/hosts/common.nix
@@ -0,0 +1,50 @@
+# This is for packages I want in all systems.
+# Keeping this list as small as possible is important,
+# since these also get installed to server,
+# which should have a small attack surface.
+{
+  lib,
+  pkgs,
+  ...
+}:
+let
+  inherit (lib.meta) hiPrioSet;
+in
+{
+  environment.systemPackages =
+    builtins.attrValues {
+      inherit (pkgs)
+        cachix
+        calc
+        delta
+        difftastic
+        eza
+        gcc
+        git
+        httpie
+        inetutils
+        jujutsu
+        just
+        lazygit
+        linuxHeaders
+        neofetch
+        microfetch
+        mprocs
+        nmap
+        ripgrep
+        smartmontools
+        television
+        trash-cli
+        util-linux
+        w3m
+        wireguard-tools
+        zip
+        zoxide
+        ;
+    }
+    ++ builtins.attrValues (hiPrioSet {
+    })
+    ++ [ (lib.hiPrio pkgs.uutils-coreutils-noprefix) ];
+  # helix as the only editor, a reasonable choice.
+  environment.variables.EDITOR = "hx";
+}
diff --git a/hosts/default.nix b/hosts/default.nix
new file mode 100644
index 0000000..12ee7fd
--- /dev/null
+++ b/hosts/default.nix
@@ -0,0 +1,70 @@
+{
+  sources,
+  nixpkgs,
+  self,
+  ...
+}:
+let
+  inherit (builtins) filter map toString;
+  inherit (nixpkgs) lib;
+  inherit (lib.attrsets) recursiveUpdate;
+  inherit (lib.filesystem) listFilesRecursive;
+  inherit (lib.lists) concatLists flatten singleton;
+  inherit (lib.strings) hasSuffix;
+  inherit (lib) nixosSystem;
+  # NOTE: This was inspired by raf, and I find this
+  # to be quite a sane way of managing all modules in my flake.
+
+  mkSystem =
+    {
+      system,
+      hostname,
+      ...
+    }@args:
+    nixosSystem {
+      specialArgs = recursiveUpdate {
+        inherit lib;
+        inputs = sources;
+        inherit self;
+      } args.specialArgs or { };
+      modules = concatLists [
+        # This is used to pre-emptively set the hostPlatform for nixpkgs.
+        # Also, we set the system hostname here.
+        (singleton {
+          networking.hostName = hostname;
+          nixpkgs.hostPlatform = system;
+        })
+        (
+          concatLists [
+            # configuration for the host, passed as an argument.
+            (singleton ./${hostname}/default.nix)
+            # common configuration,  which all hosts share.
+            (singleton ./common.nix)
+            # Import all files called module.nix from my modules directory.
+            (map toString (listFilesRecursive ../modules) |> filter (hasSuffix "module.nix"))
+            (map toString (listFilesRecursive ../modules) |> filter (hasSuffix ".mod.nix"))
+          ]
+          |> flatten
+        )
+      ];
+    };
+in
+{
+  temperance = mkSystem {
+    system = "x86_64-linux";
+    hostname = "temperance";
+  };
+
+  hermit = mkSystem {
+    system = "x86_64-linux";
+    hostname = "hermit";
+  };
+  tower = mkSystem {
+    system = "aarch64-linux";
+    hostname = "tower";
+  };
+  # world = mkSystem {
+  #   system = "x86_64-linux";
+  #   hostname = "world";
+  # };
+}
diff --git a/shell.nix b/shell.nix
deleted file mode 100644
index 505408b..0000000
--- a/shell.nix
+++ /dev/null
@@ -1,12 +0,0 @@
-{
-  pkgs ? import <nixpkgs> { },
-  sources ? import ./npins,
-}:
-pkgs.mkShellNoCC {
-
-  packages = [
-    (pkgs.callPackage (sources.npins + "/npins.nix") { })
-    pkgs.nil
-    pkgs.nixfmt
-  ];
-}