diff --git a/BUILD.gn b/BUILD.gn
index 0262cb1f36..a96f77d1f6 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -311,18 +311,19 @@ if (pw_BUILD_BROKEN_GROUPS) {
     toolchain_prefix =
         "$dir_pigweed/targets/lm3s6965evb_qemu:lm3s6965evb_qemu_clang_"
   }
-}
-group("qemu_gcc_size_optimized") {
-  deps = [ ":pigweed_default($dir_pigweed/targets/lm3s6965evb_qemu:lm3s6965evb_qemu_gcc_size_optimized)" ]
-}
-group("qemu_gcc") {
-  deps = [ ":qemu_gcc_size_optimized" ]
-}
-group("qemu_clang_size_optimized") {
-  deps = [ ":pigweed_default($dir_pigweed/targets/lm3s6965evb_qemu:lm3s6965evb_qemu_clang_size_optimized)" ]
-}
-group("qemu_clang") {
-  deps = [ ":qemu_clang_size_optimized" ]
+} else {
+  group("qemu_gcc_size_optimized") {
+    deps = [ ":pigweed_default($dir_pigweed/targets/lm3s6965evb_qemu:lm3s6965evb_qemu_gcc_size_optimized)" ]
+  }
+  group("qemu_gcc") {
+    deps = [ ":qemu_gcc_size_optimized" ]
+  }
+  group("qemu_clang_size_optimized") {
+    deps = [ ":pigweed_default($dir_pigweed/targets/lm3s6965evb_qemu:lm3s6965evb_qemu_clang_size_optimized)" ]
+  }
+  group("qemu_clang") {
+    deps = [ ":qemu_clang_size_optimized" ]
+  }
 }
 
 # Run clang-tidy on pigweed_default with pw_strict_host_clang_debug toolchain options.
diff --git a/pw_presubmit/py/pw_presubmit/pigweed_presubmit.py b/pw_presubmit/py/pw_presubmit/pigweed_presubmit.py
index 050865518f..f626008756 100755
--- a/pw_presubmit/py/pw_presubmit/pigweed_presubmit.py
+++ b/pw_presubmit/py/pw_presubmit/pigweed_presubmit.py
@@ -202,7 +202,10 @@ def _gn_combined_build_check_targets() -> Sequence[str]:
     name='gn_combined_build_check',
     doc='Run most host and device (QEMU) tests.',
     path_filter=_BUILD_FILE_FILTER,
-    gn_args=dict(pw_C_OPTIMIZATION_LEVELS=_OPTIMIZATION_LEVELS),
+    gn_args=dict(
+        pw_C_OPTIMIZATION_LEVELS=_OPTIMIZATION_LEVELS,
+        pw_BUILD_BROKEN_GROUPS=True,  # Enable to fully test the GN build
+    ),
     ninja_targets=_gn_combined_build_check_targets(),
 )