diff --git a/builder.nix b/builder.nix
index 0355d7b..8a6a891 100644
--- a/builder.nix
+++ b/builder.nix
@@ -27,122 +27,9 @@
 }:
 with pkgs;
 let
-  fetchSums = url: sha256:
-    let
-      sumsFile = fetchurl {
-        url = "${url}/sha256sums";
-        inherit sha256;
-      };
-
-      filesSha256 =
-        builtins.foldl' (filesSha256: line:
-          let
-            m = builtins.match "([0-9a-f]+) \\*(.+)" line;
-          in
-            if builtins.isList m && builtins.length m == 2
-            then filesSha256 // {
-              ${builtins.elemAt m 1} = builtins.elemAt m 0;
-            } else filesSha256
-        ) {} (lib.splitString "\n" (builtins.readFile sumsFile));
-
-    in
-      builtins.mapAttrs (file: sha256:
-        fetchurl {
-          url = "${url}/${file}";
-          inherit sha256;
-        }
-      ) filesSha256;
-
-  fetchPackages = url: packagesContent:
-    let
-      parsedPackages = map (section:
-        builtins.foldl' (data: line:
-          let
-            m = builtins.match "(.+): (.+)" line;
-          in
-            if builtins.isList m && builtins.length m == 2
-            then data // {
-              ${builtins.elemAt m 0} = builtins.elemAt m 1;
-            } else data
-        ) {} (lib.splitString "\n" section)
-      ) (lib.splitString "\n\n" packagesContent);
-
-    in
-      builtins.foldl' (variantFiles: parsed:
-        if parsed ? Filename && parsed ? SHA256sum
-        then
-          variantFiles // {
-            ${parsed.Filename} = fetchurl {
-              url = "${url}/${parsed.Filename}";
-              sha256 = parsed.SHA256sum;
-            };
-          }
-        else
-          variantFiles
-      ) {} parsedPackages;
-
-  baseUrl = "https://downloads.openwrt.org/releases/${release}";
-
-  variantFiles = fetchSums "${baseUrl}/targets/${target}/${variant}" sha256;
-
-  variantPackages = runCommandNoCC "openwrt-${release}-${target}-${variant}-packages" {} ''
-    mkdir packages
-    ${lib.concatMapStrings (file:
-      lib.optionalString (lib.hasPrefix "packages/" file) ''
-        ln -s ${variantFiles.${file}} ${file}
-      '') (builtins.attrNames variantFiles)}
-    mv packages $out
-  '';
-
-  feedsPackagesFile = builtins.mapAttrs (feed: sha256:
-    fetchurl {
-      url = "${baseUrl}/packages/${arch}/${feed}/Packages";
-      inherit sha256;
-    }
-  ) feedsSha256;
-
-  feedsFiles = builtins.mapAttrs (feed: packagesFile:
-    fetchPackages "${baseUrl}/packages/${arch}/${feed}" (builtins.readFile packagesFile)
-  ) feedsPackagesFile;
-
-  feedsPackages = builtins.mapAttrs (feed: files:
-    runCommandNoCC "openwrt-${release}-${arch}-${feed}-packages" {} ''
-      mkdir $out
-      ln -s ${feedsPackagesFile.${feed}} $out/Packages
-      ${lib.concatMapStrings (file: ''
-        ln -s ${files.${file}} $out/${file}
-      '') (builtins.attrNames files)}
-    ''
-  ) feedsFiles;
-
-  openwrtConfigFile = stdenv.mkDerivation {
-    name = "openwrt-${release}-${target}-${variant}.config";
-    src = variantFiles."openwrt-imagebuilder-${release}-${target}-${variant}.${hostPlatform.uname.system}-${hostPlatform.uname.processor}.tar.xz";
-    phases = [ "unpackPhase" "installPhase" ];
-    installPhase = ''
-      cp .config $out
-    '';
-  };
-
-  openwrtConfig = builtins.foldl' (openwrtConfig: line:
-    let
-      m1 = builtins.match "(.+)=\"(.+)\"" line;
-      m2 = builtins.match "(.+)=(.+)" line;
-    in
-      if builtins.isList m1 && builtins.length m1 == 2
-      then openwrtConfig // {
-        ${builtins.elemAt m1 0} = builtins.elemAt m1 1;
-      }
-      else if builtins.isList m2 && builtins.length m2 == 2
-      then openwrtConfig // {
-        ${builtins.elemAt m2 0} = builtins.elemAt m2 1;
-      }
-      else openwrtConfig
-  ) {} (
-    lib.splitString "\n" (builtins.readFile openwrtConfigFile)
-  );
-
-  arch = openwrtConfig.CONFIG_TARGET_ARCH_PACKAGES;
+  inherit (import ./files.nix {
+    inherit pkgs release target variant sha256 feedsSha256;
+  }) arch variantPackages variantFiles feedsPackages;
 in
 
 stdenv.mkDerivation {
diff --git a/files.nix b/files.nix
new file mode 100644
index 0000000..1e6316e
--- /dev/null
+++ b/files.nix
@@ -0,0 +1,110 @@
+{ pkgs ? import <nixpkgs> {}
+# OpenWRT release
+, release ? "21.02.3"
+# OpenWRT target
+, target
+, variant ? "generic"
+# Checksum of the `sha256sums` file
+, sha256
+# Checksum of a feed's `Packages` file
+, feedsSha256
+}:
+with pkgs;
+let
+  fetchSums = url: sha256:
+    let
+      sumsFile = fetchurl {
+        url = "${url}/sha256sums";
+        inherit sha256;
+      };
+
+      filesSha256 =
+        builtins.foldl' (filesSha256: line:
+          let
+            m = builtins.match "([0-9a-f]+) \\*(.+)" line;
+          in
+            if builtins.isList m && builtins.length m == 2
+            then filesSha256 // {
+              ${builtins.elemAt m 1} = builtins.elemAt m 0;
+            } else filesSha256
+        ) {} (lib.splitString "\n" (builtins.readFile sumsFile));
+
+    in
+      builtins.mapAttrs (file: sha256:
+        fetchurl {
+          url = "${url}/${file}";
+          inherit sha256;
+        }
+      ) filesSha256;
+
+  fetchPackages = url: packagesContent:
+    let
+      parsedPackages = map (section:
+        builtins.foldl' (data: line:
+          let
+            m = builtins.match "(.+): (.+)" line;
+          in
+            if builtins.isList m && builtins.length m == 2
+            then data // {
+              ${builtins.elemAt m 0} = builtins.elemAt m 1;
+            } else data
+        ) {} (lib.splitString "\n" section)
+      ) (lib.splitString "\n\n" packagesContent);
+
+    in
+      builtins.foldl' (variantFiles: parsed:
+        if parsed ? Filename && parsed ? SHA256sum
+        then
+          variantFiles // {
+            ${parsed.Filename} = fetchurl {
+              url = "${url}/${parsed.Filename}";
+              sha256 = parsed.SHA256sum;
+            };
+          }
+        else
+          variantFiles
+      ) {} parsedPackages;
+
+  baseUrl = "https://downloads.openwrt.org/releases/${release}";
+
+  variantFiles = fetchSums "${baseUrl}/targets/${target}/${variant}" sha256;
+
+  variantPackages = runCommandNoCC "openwrt-${release}-${target}-${variant}-packages" {} ''
+    mkdir packages
+    ${lib.concatMapStrings (file:
+      lib.optionalString (lib.hasPrefix "packages/" file) ''
+        ln -s ${variantFiles.${file}} ${file}
+      '') (builtins.attrNames variantFiles)}
+    mv packages $out
+  '';
+
+  feedsPackagesFile = builtins.mapAttrs (feed: sha256:
+    fetchurl {
+      url = "${baseUrl}/packages/${arch}/${feed}/Packages";
+      inherit sha256;
+    }
+  ) feedsSha256;
+
+  feedsFiles = builtins.mapAttrs (feed: packagesFile:
+    fetchPackages "${baseUrl}/packages/${arch}/${feed}" (builtins.readFile packagesFile)
+  ) feedsPackagesFile;
+
+  feedsPackages = builtins.mapAttrs (feed: files:
+    runCommandNoCC "openwrt-${release}-${arch}-${feed}-packages" {} ''
+      mkdir $out
+      ln -s ${feedsPackagesFile.${feed}} $out/Packages
+      ${lib.concatMapStrings (file: ''
+        ln -s ${files.${file}} $out/${file}
+      '') (builtins.attrNames files)}
+    ''
+  ) feedsFiles;
+
+  arch = (builtins.fromJSON (
+    builtins.readFile (
+      variantFiles."profiles.json"
+    )
+  )).arch_packages;
+
+in {
+  inherit variantFiles variantPackages feedsFiles feedsPackages;
+}