diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index edb2d39..fb3b42c 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -48,7 +48,7 @@ jobs:
       - id: enumerate_packages
         name: Get all packages
         run: |
-          echo "FLAKE_OUTPUTS=$(python3 ./.github/workflows/get_all_packages.py)" >> $GITHUB_ENV
+          echo "FLAKE_OUTPUTS=$(python3 ./.github/workflows/get_all_packages.py | tr '\n' ' ')" >> $GITHUB_ENV
       - name: Build All
         run: |
           set +e
diff --git a/.github/workflows/get_all_packages.py b/.github/workflows/get_all_packages.py
index 54c4bf4..f89fbda 100644
--- a/.github/workflows/get_all_packages.py
+++ b/.github/workflows/get_all_packages.py
@@ -2,20 +2,33 @@
 import json
 import subprocess
 
-flake_meta_process = subprocess.Popen(
-    ["nix", "flake", "show", "--json"],
-    stdout=subprocess.PIPE,
-    stderr=subprocess.PIPE,
-    encoding="utf8",
-)
-flake_meta_process.wait()
-if flake_meta_process.returncode:
-    print(f"Failed to get flake metadata:", file=sys.stderr)
-    print(flake_meta_process.stderr.read(), file=sys.stderr)
-    exit(-1)
-flake_meta = json.load(flake_meta_process.stdout)
+def run(purpose, *args):
+    process = subprocess.Popen(
+        [*args],
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        encoding="utf8",
+    )
+    process.wait()
+    if process.returncode:
+        print(f"Failed to {purpose}:", file=sys.stderr)
+        print(process.stderr.read(), file=sys.stderr)
+        exit(-1)
+    return process.stdout
+
+flake_meta = json.load(run("get flake metadata", "nix", "flake", "show", "--json"))
 packages = flake_meta["packages"]
 for platform, packages in packages.items():
     for package, package_info in packages.items():
-        if len(package_info):
-            print(f".#packages.{platform}.{package}", end=" ")
+        if len(package_info) == 0:
+            continue
+        tgt = f".#packages.{platform}.{package}"
+        outputs = []
+        drv = json.load(run(f"get derivation info for {package}", "nix", "derivation", "show", tgt))
+        keys = list(drv.keys())
+        if len(keys) != 1:
+            print(f"'nix derivation show' unexpectedly returned {len(keys)} paths, expected exactly 1: {tgt}", file=sys.stderr)
+            exit(-1)
+        output_list = drv[keys[0]]["outputs"]
+        for output in output_list:
+            print(f"{tgt}.{output}")
diff --git a/flake.nix b/flake.nix
index 79b0d5d..479fd66 100644
--- a/flake.nix
+++ b/flake.nix
@@ -60,7 +60,7 @@
         )
         (
           self.composePythonOverlay (pkgs': pkgs: pypkgs': pypkgs: let
-            callPythonPackage = lib.callPackageWith (pkgs' // pkgs'.python3.pkgs);
+            callPythonPackage = lib.callPackageWith (pkgs' // pypkgs');
           in {
             kfactory = pypkgs.kfactory.overrideAttrs (attrs': attrs: {
               version = "1.9.3";
diff --git a/nix/yosys.nix b/nix/yosys.nix
index b194d81..b2ac51d 100644
--- a/nix/yosys.nix
+++ b/nix/yosys.nix
@@ -57,6 +57,7 @@
   bash,
   version ? "0.54",
   sha256 ? "sha256-meKlZh6ZiiPHwQCvS7Y667lvE9XWgIaual8c6SDpeDw=",
+  darwin, # To fix codesigning issue for pyosys
   # For environments
   yosys,
   buildEnv,
@@ -89,7 +90,7 @@ in let
       pkg-config
       bison
       flex
-    ];
+    ] ++ lib.optionals clangStdenv.isDarwin [darwin.autoSignDarwinBinariesHook];
 
     propagatedBuildInputs = [
       tcl