diff --git a/lib/build-clan/interface.nix b/lib/build-clan/interface.nix
index 8dd3abf74..df4743980 100644
--- a/lib/build-clan/interface.nix
+++ b/lib/build-clan/interface.nix
@@ -3,6 +3,7 @@ let
   types = lib.types;
 in
 {
+
   options = {
     # Required options
     directory = lib.mkOption {
@@ -69,18 +70,6 @@ in
       default = { };
     };
 
-    pkgsForSystem = lib.mkOption {
-      type = types.functionTo (types.nullOr types.attrs);
-      default = _: null;
-      defaultText = "Lambda :: String -> { ... } | null";
-      description = ''
-        A function that maps from architecture to pkg. `( string -> pkgs )`
-
-        If specified this nixpkgs will be only imported once for each system.
-        This improves performance, but all nipxkgs.* options will be ignored.
-      '';
-    };
-
     # Outputs
     nixosConfigurations = lib.mkOption {
       # Hide from documentation.
@@ -112,4 +101,5 @@ in
       };
     };
   };
+
 }
diff --git a/lib/build-clan/module.nix b/lib/build-clan/module.nix
index 079a7762c..072b16c98 100644
--- a/lib/build-clan/module.nix
+++ b/lib/build-clan/module.nix
@@ -9,7 +9,6 @@ let
   inherit (config)
     directory
     machines
-    pkgsForSystem
     specialArgs
     ;
 
@@ -58,7 +57,7 @@ let
               # Settings
               clan.core.clanDir = directory;
               # Inherited from clan wide settings
-              # TODO: remove these
+              # TODO: remove these`
               clan.core.name = config.inventory.meta.name;
               clan.core.icon = config.inventory.meta.icon;
 
@@ -105,7 +104,12 @@ let
           name: _:
           nixosConfiguration {
             inherit name system;
-            pkgs = pkgsForSystem system;
+
+            # We removed pkgsForSystems because we have the problem that nixpkgs.* options are then ignored
+            # However our current model is to have the hardware config read and then set nixpkgs.hostPlatform automatically
+            # which gets ignored if we set pkgsForSystems. pkgsForSystems also needed to be set as else 
+            # pkgs was equals to null in nixosConfiguration above which broke something else
+            pkgs = nixpkgs.legacyPackages.${system};
           }
         ) allMachines
       )
@@ -122,7 +126,7 @@ let
             args
             // {
               inherit name system;
-              pkgs = pkgsForSystem system;
+              pkgs = nixpkgs.legacyPackages.${system};
             }
           )
         ) allMachines
diff --git a/pkgs/clan-cli/clan_cli/machines/install.py b/pkgs/clan-cli/clan_cli/machines/install.py
index 05fbadc9c..52d2ff440 100644
--- a/pkgs/clan-cli/clan_cli/machines/install.py
+++ b/pkgs/clan-cli/clan_cli/machines/install.py
@@ -15,6 +15,7 @@ from clan_cli.completions import (
     complete_machines,
     complete_target_host,
 )
+from clan_cli.errors import ClanError
 from clan_cli.facts.generate import generate_facts
 from clan_cli.machines.hardware import HardwareConfig
 from clan_cli.machines.machines import Machine
@@ -25,10 +26,6 @@ from clan_cli.vars.generate import generate_vars
 log = logging.getLogger(__name__)
 
 
-class ClanError(Exception):
-    pass
-
-
 @dataclass
 class InstallOptions:
     # flake to install
@@ -85,9 +82,6 @@ def install_machine(opts: InstallOptions) -> None:
         if opts.no_reboot:
             cmd.append("--no-reboot")
 
-        if opts.build_on_remote:
-            cmd.append("--build-on-remote")
-
         if opts.update_hardware_config is not HardwareConfig.NONE:
             cmd.extend(
                 [
@@ -108,6 +102,10 @@ def install_machine(opts: InstallOptions) -> None:
                 "IdentitiesOnly=yes",
             ]
 
+        if not machine.can_build_locally or opts.build_on_remote:
+            log.info("Architecture mismatch. Building on remote machine")
+            cmd.append("--build-on-remote")
+
         if machine.target_host.port:
             cmd += ["--ssh-port", str(machine.target_host.port)]
         if opts.kexec:
diff --git a/pkgs/clan-cli/clan_cli/machines/machines.py b/pkgs/clan-cli/clan_cli/machines/machines.py
index 2818414a6..b02599eac 100644
--- a/pkgs/clan-cli/clan_cli/machines/machines.py
+++ b/pkgs/clan-cli/clan_cli/machines/machines.py
@@ -46,6 +46,32 @@ class Machine:
     def __repr__(self) -> str:
         return str(self)
 
+    @property
+    def system(self) -> str:
+        # We filter out function attributes because they are not serializable.
+        attr = f"""
+            (let
+                machine = ((builtins.getFlake "{self.flake}").nixosConfigurations.{self.name});
+            in
+            {{ x =  machine.pkgs.stdenv.hostPlatform.system; }}).x
+            """
+        if attr in self._eval_cache:
+            output = self._eval_cache[attr]
+        else:
+            output = run_no_stdout(
+                nix_eval(["--impure", "--expr", attr])
+            ).stdout.strip()
+            self._eval_cache[attr] = output
+        value = json.loads(output)
+        return value
+
+    @property
+    def can_build_locally(self) -> bool:
+        # TODO: We could also use the function pkgs.stdenv.hostPlatform.canExecute
+        # but this is good enough for now.
+        output = nix_config()
+        return self.system == output["system"]
+
     @property
     def deployment(self) -> dict:
         if self.cached_deployment is not None:
@@ -173,7 +199,6 @@ class Machine:
         method: Literal["eval", "build"],
         attr: str,
         extra_config: None | dict = None,
-        impure: bool = False,
         nix_options: list[str] | None = None,
     ) -> str | Path:
         """
@@ -215,12 +240,6 @@ class Machine:
                 "dirtyRevision" in metadata
                 or "dirtyRev" in metadata["locks"]["nodes"]["clan-core"]["locked"]
             ):
-                # if not impure:
-                #     raise ClanError(
-                #         "The machine has a dirty revision, and impure mode is not allowed"
-                #     )
-                # else:
-                #     args += ["--impure"]
                 args += ["--impure"]
 
             args += [
@@ -254,7 +273,6 @@ class Machine:
         attr: str,
         refresh: bool = False,
         extra_config: None | dict = None,
-        impure: bool = False,
         nix_options: list[str] | None = None,
     ) -> str:
         """
@@ -266,7 +284,7 @@ class Machine:
         if attr in self._eval_cache and not refresh and extra_config is None:
             return self._eval_cache[attr]
 
-        output = self.nix("eval", attr, extra_config, impure, nix_options)
+        output = self.nix("eval", attr, extra_config, nix_options)
         if isinstance(output, str):
             self._eval_cache[attr] = output
             return output
@@ -278,7 +296,6 @@ class Machine:
         attr: str,
         refresh: bool = False,
         extra_config: None | dict = None,
-        impure: bool = False,
         nix_options: list[str] | None = None,
     ) -> Path:
         """
@@ -291,7 +308,7 @@ class Machine:
         if attr in self._build_cache and not refresh and extra_config is None:
             return self._build_cache[attr]
 
-        output = self.nix("build", attr, extra_config, impure, nix_options)
+        output = self.nix("build", attr, extra_config, nix_options)
         if isinstance(output, Path):
             self._build_cache[attr] = output
             return output