diff --git a/README.md b/README.md
index 9af78de..fe49084 100644
--- a/README.md
+++ b/README.md
@@ -4,8 +4,34 @@ Develop Zephyr projects using Nix
 
 ## Features
 
-- SDK packaging
-- Host tools packaging
+* SDK packaging
+  * `sdk`
+
+  The minimal SDK.
+  Can be overriden with additional targets.
+
+  ``` nix
+  sdk.override {
+    targets = [
+      "arm-zephyr-eabi"
+    ];
+  }
+  ```
+
+  * `sdkFull`
+
+  SDK with all targets enabled.
+
+* Host tools packaging
+
+  * `hosttools`
+
+  Binary `hosttools` from the Zephyr SDK.
+  Because of libc incompatibilities not all binaries in this derivation actually works.
+
+  * `hosttools-nix`
+
+  A re-packaging of the Zephyr SDK hosttools using nixpkgs packages.
 
 ## Basic usage
 
@@ -29,11 +55,11 @@ mkShell {
     ninja
   ];
 
-  env.ZEPHYR_SDK_INSTALL_DIR = zephyr.sdk.overrideAttrs(old: {
-    targets = old.targets ++ [
+  env.ZEPHYR_SDK_INSTALL_DIR = zephyr.sdk.override {
+    targets = [
       "arm-zephyr-eabi"
     ];
-  });
+  };
 }
 ```
 
diff --git a/default.nix b/default.nix
index 2bcac98..7db89c5 100644
--- a/default.nix
+++ b/default.nix
@@ -1,28 +1,21 @@
 { callPackage
-, stdenv
 , zephyr-src
 , pyproject-nix
 , lib
 , fetchurl
-, which
-, autoPatchelfHook
-, cmake
 , python38
-, pkgs
 }:
 
 let
-  sdk = lib.importJSON ./sdk.json;
-  inherit (sdk) version;
+  sdk' = lib.importJSON ./sdk.json;
+  inherit (sdk') version;
 
-  python3 = python38;
-
-  platform =
+  getPlatform = stdenv:
     if stdenv.isLinux then "linux"
     else if stdenv.isDarwin then "macos"
     else throw "Unsupported platform";
 
-  arch =
+  getArch = stdenv:
     if stdenv.isLinux then stdenv.hostPlatform.linuxArch
     else if stdenv.isDarwin then stdenv.hostPlatform.darwinArch
     else throw "Unsupported arch";
@@ -31,11 +24,15 @@ let
 
   fetchSDKFile = file: fetchurl {
     url = "${baseURL}/${file}";
-    sha256 = sdk.files.${file};
+    sha256 = sdk'.files.${file};
+  };
+
+  sdkArgs = {
+    python3 = python38;
   };
 
 in
-{
+rec {
   # Zephyr/west Python environment.
   pythonEnv = callPackage ./python.nix {
     inherit zephyr-src;
@@ -43,80 +40,126 @@ in
   };
 
   # Pre-package Zephyr SDK.
-  sdk = stdenv.mkDerivation (finalAttrs: {
-    pname = "zephyr-sdk";
-    inherit version;
+  sdk = callPackage
+    ({ stdenv
+     , which
+     , cmake
+     , autoPatchelfHook
+     , python3
+     , targets ? [ ]
+     }:
+      let
+        platform = getPlatform stdenv;
+        arch = getArch stdenv;
+      in
+      stdenv.mkDerivation {
+        pname = "zephyr-sdk";
+        inherit version;
 
-    srcs = [
-      (fetchSDKFile "zephyr-sdk-${version}_${platform}-${arch}_minimal.tar.xz")
-    ] ++ map fetchSDKFile (map (target: "toolchain_${platform}-${arch}_${target}.tar.xz") finalAttrs.targets);
+        srcs = [
+          (fetchSDKFile "zephyr-sdk-${version}_${platform}-${arch}_minimal.tar.xz")
+        ] ++ map fetchSDKFile (map (target: "toolchain_${platform}-${arch}_${target}.tar.xz") targets);
 
-    targets = [ ];  # Zephyr targets
+        passthru = {
+          inherit platform arch targets;
+        };
 
-    nativeBuildInputs = [ which cmake autoPatchelfHook ];
+        nativeBuildInputs = [ which cmake autoPatchelfHook ];
 
-    buildInputs = [ stdenv.cc.cc python38 ];
+        buildInputs = [ stdenv.cc.cc python3 ];
 
-    dontBuild = true;
-    dontUseCmakeConfigure = true;
+        dontBuild = true;
+        dontUseCmakeConfigure = true;
 
-    sourceRoot = ".";
+        sourceRoot = ".";
 
-    installPhase = ''
-      runHook preInstall
+        installPhase = ''
+          runHook preInstall
 
-      rm zephyr-sdk-$version/zephyr-sdk-${arch}-hosttools-standalone-*.sh
-      rm zephyr-sdk-$version/setup.sh;
+          rm zephyr-sdk-$version/zephyr-sdk-${arch}-hosttools-standalone-*.sh
+          rm zephyr-sdk-$version/setup.sh;
 
-      mv zephyr-sdk-$version $out
-      mv $(ls | grep -v env-vars) $out/
+          mv zephyr-sdk-$version $out
+          mv $(ls | grep -v env-vars) $out/
 
-      runHook postInstall
-    '';
-  });
+          runHook postInstall
+        '';
+      })
+    sdkArgs;
+
+  # # SDK with all targets selected
+  sdkFull =
+    let
+      inherit (sdk.passthru) platform arch;
+      mToolchain = builtins.match "toolchain_${platform}-${arch}_(.+)\.tar\.xz";
+      allTargets = map (x: builtins.head (mToolchain x)) (builtins.filter (f: mToolchain f != null) (lib.attrNames sdk'.files));
+    in
+    sdk.override {
+      targets = allTargets;
+    };
 
   # Binary host tools provided by the Zephyr project.
-  hosttools = stdenv.mkDerivation {
-    pname = "zephyr-sdk-hosttools";
-    inherit version;
+  hosttools = callPackage
+    ({ stdenv
+     , which
+     , autoPatchelfHook
+     , python3
+     }:
+      let
+        platform = getPlatform stdenv;
+        arch = getArch stdenv;
+      in
+      stdenv.mkDerivation {
+        pname = "zephyr-sdk-hosttools";
+        inherit version;
 
-    src = fetchSDKFile "hosttools_${platform}-${arch}.tar.xz";
+        src = fetchSDKFile "hosttools_${platform}-${arch}.tar.xz";
 
-    nativeBuildInputs = [ which autoPatchelfHook ];
+        nativeBuildInputs = [ which autoPatchelfHook ];
 
-    buildInputs = [ python3 ];
+        buildInputs = [ python3 ];
 
-    dontBuild = true;
+        dontBuild = true;
 
-    sourceRoot = ".";
+        sourceRoot = ".";
 
-    installPhase = ''
-      runHook preInstall
-      mkdir -p $out/usr/share/zephyr/hosttools
-      ./zephyr-sdk-${arch}-hosttools-standalone-*.sh -d $out/usr/share/zephyr/hosttools
-      ln -s $out/usr/share/zephyr/hosttools/sysroots/${arch}-pokysdk-${platform}/usr/bin $out/bin
-      runHook postInstall
-    '';
-  };
+        installPhase = ''
+          runHook preInstall
+          mkdir -p $out/usr/share/zephyr/hosttools
+          ./zephyr-sdk-${arch}-hosttools-standalone-*.sh -d $out/usr/share/zephyr/hosttools
+          ln -s $out/usr/share/zephyr/hosttools/sysroots/${arch}-pokysdk-${platform}/usr/bin $out/bin
+          runHook postInstall
+        '';
+      })
+    sdkArgs;
 
   # A variant of hosttools, but all tools are taken from nixpkgs.
-  hosttools-nix = stdenv.mkDerivation {
-    name = "zephyr-sdk-hosttools-nix";
+  hosttools-nix = callPackage
+    ({ stdenv
+     , bossa
+     , dtc
+     , nettle
+     , openocd
+     , qemu_full
+     , shared-mime-info
+     }: stdenv.mkDerivation {
+      name = "zephyr-sdk-hosttools-nix";
 
-    dontUnpack = true;
-    dontBuild = true;
+      dontUnpack = true;
+      dontBuild = true;
 
-    propagatedBuildInputs = with pkgs; [
-      bossa
-      dtc
-      nettle
-      openocd
-      qemu_full
-      shared-mime-info
-    ];
+      propagatedBuildInputs = [
+        bossa
+        dtc
+        nettle
+        openocd
+        qemu_full
+        shared-mime-info
+      ];
 
-    installPhase = ''
-      mkdir $out
-    '';
-  };
+      installPhase = ''
+        mkdir $out
+      '';
+    })
+    { };
 }
diff --git a/flake.nix b/flake.nix
index 224d0df..c995bed 100644
--- a/flake.nix
+++ b/flake.nix
@@ -18,16 +18,17 @@
     {
       packages =
         forAllSystems
-        (
-          system:
-          let
-            pkgs = nixpkgs.legacyPackages.${system};
-          in
-          pkgs.callPackages ./. {
-            zephyr-src = zephyr;
-            inherit pyproject-nix;
-          }
-        );
+          (
+            system:
+            let
+              pkgs = nixpkgs.legacyPackages.${system};
+            in
+            builtins.removeAttrs
+              (pkgs.callPackage ./. {
+                zephyr-src = zephyr;
+                inherit pyproject-nix;
+              }) [ "override" "overrideDerivation" ]
+          );
     }
   );
 }