diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index dfac569..6f9e995 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -188,6 +188,16 @@ jobs:
           lipo -info build/OpenMix.app/Contents/MacOS/OpenMix | grep -q x86_64
           lipo -info build/OpenMix.app/Contents/MacOS/OpenMix | grep -q arm64
 
+      # the app only uses SQLite; the Mimer driver's missing client library
+      # makes macdeployqt spew ERRORs, and ODBC/psql draw private-API warnings.
+      # Prune after configure/build: CMake's imported plugin targets error out
+      # if the dylibs disappear before configure
+      - name: Prune unused Qt SQL drivers
+        run: |
+          rm -f "$QT_ROOT_DIR/plugins/sqldrivers/"libqsqlmimer*.dylib \
+                "$QT_ROOT_DIR/plugins/sqldrivers/"libqsqlodbc*.dylib \
+                "$QT_ROOT_DIR/plugins/sqldrivers/"libqsqlpsql*.dylib
+
       - name: Package (DMG)
         run: cd build && cpack -G DragNDrop
 
@@ -227,8 +237,14 @@ jobs:
       - name: Remove untrusted brew taps
         run: brew untap aws/tap 2>/dev/null || true
 
+      # fetched from the pinned upstream release (same version CMake bundles);
+      # the homebrew sparkle cask is deprecated and disabled after 2026-09-01
       - name: Install Sparkle tools
-        run: brew install --cask sparkle || brew install sparkle
+        run: |
+          curl -fsSL -o /tmp/sparkle.tar.xz \
+            https://github.com/sparkle-project/Sparkle/releases/download/2.6.4/Sparkle-2.6.4.tar.xz
+          mkdir -p /tmp/sparkle
+          tar -xf /tmp/sparkle.tar.xz -C /tmp/sparkle
 
       - name: Download artifacts
         uses: actions/download-artifact@v8
@@ -243,7 +259,8 @@ jobs:
           mkdir -p site/download/${TAG}
           cp OpenMix-macos/* OpenMix-windows/* OpenMix-linux/* site/download/${TAG}/ 2>/dev/null || true
 
-          SIGN=$(find /opt/homebrew /usr/local -name sign_update -type f 2>/dev/null | head -1)
+          SIGN=/tmp/sparkle/bin/sign_update
+          [ -x "$SIGN" ] || SIGN=""
           DMG=$(ls OpenMix-macos/*.dmg | head -1)
           if [ -n "$SPARKLE_KEY" ] && [ -n "$SIGN" ] && [ -n "$DMG" ]; then
             echo "$SPARKLE_KEY" > /tmp/ed_key
diff --git a/tests/test_playback_profiles.cpp b/tests/test_playback_profiles.cpp
index bb0ab09..59383a4 100644
--- a/tests/test_playback_profiles.cpp
+++ b/tests/test_playback_profiles.cpp
@@ -15,7 +15,8 @@ using namespace OpenMix;
 namespace {
 LoopbackProtocol* makeConnectedLoopback(QObject* parent) {
     auto* mixer = new LoopbackProtocol(MixerCapabilities::forConsole(ConsoleType::X32), parent);
-    mixer->connect("loopback", 0); // sets state Connected synchronously
+    [[maybe_unused]] const bool ok = mixer->connect("loopback", 0); // Connected synchronously
+    Q_ASSERT(ok);
     return mixer;
 }
 } // namespace