diff --git a/scripts/generate_pack.py b/scripts/generate_pack.py
index 31d0d560..1edf01de 100644
--- a/scripts/generate_pack.py
+++ b/scripts/generate_pack.py
@@ -2041,6 +2041,7 @@ def _run_manifest_mode(
                     regions=getattr(args, "regions", None),
                     target_name=args.target,
                     offline=args.offline,
+                    required_only=required_only,
                 )
                 narrow_suffix = "".join(
                     tag.lower()
@@ -2660,6 +2661,7 @@ def _manifest_core_entries(
     manifest_files: list,
     omitted_by_destination: dict,
     record_omission,
+    required_only: bool = False,
 ) -> int:
     """Add the files a platform's cores need but its list does not name.
 
@@ -2671,6 +2673,8 @@ def _manifest_core_entries(
     total_size = 0
     extras_pfx = _detect_extras_prefix(config, base_dest)
     for fe in core_files:
+        if required_only and fe.get("required") is False:
+            continue
         dest = sanitize_pack_path(fe.get("destination", fe["name"]))
         if not dest:
             continue
@@ -2770,6 +2774,7 @@ def generate_manifest(
     regions: list[str] | None = None,
     target_name: str | None = None,
     offline: bool | None = None,
+    required_only: bool = False,
 ) -> dict:
     """Generate a JSON manifest for a platform (same resolution as generate_pack).
 
@@ -2871,6 +2876,8 @@ def generate_manifest(
         )
         for sys_id, system in sorted(pack_systems.items()):
             for file_entry in system.get("files", []):
+                if required_only and file_entry.get("required") is False:
+                    continue
                 dest = sanitize_pack_path(file_entry.get("destination", file_entry["name"]))
                 if not dest:
                     continue
@@ -2985,7 +2992,7 @@ def generate_manifest(
         core_files, config, db, bios_dir, base_dest, repo_root,
         zip_contents, offline, region_drops, case_insensitive,
         seen_destinations, seen_lower, seen_parents, manifest_files,
-        omitted_by_destination, record_omission,
+        omitted_by_destination, record_omission, required_only,
     )
 
     # No phase 3 (data directories) -skipped for manifest
diff --git a/tests/test_e2e.py b/tests/test_e2e.py
index 026332c1..2a97db6e 100644
--- a/tests/test_e2e.py
+++ b/tests/test_e2e.py
@@ -3406,6 +3406,44 @@ class TestE2E(unittest.TestCase):
             registry["platforms"]["emudeck"]["install"],
         )
 
+    def test_91_manifest_required_only_drops_optional_files(self):
+        """A manifest named _required must hold only the required files.
+
+        The filename carried the narrowing while the content did not, so
+        install.py fetched every optional file for a user who asked for the
+        required set, and --all-variants wrote three manifests that duplicated
+        their non-required twins.
+        """
+        from generate_pack import generate_manifest
+
+        registry_path = os.path.join(self.platforms_dir, "_test_registry.yml")
+        with open(registry_path, "w") as fh:
+            yaml.dump({"platforms": {"test_existence": {"install": {}}}}, fh)
+
+        def names(required_only):
+            manifest = generate_manifest(
+                "test_existence",
+                self.platforms_dir,
+                self.db,
+                self.bios_dir,
+                registry_path,
+                emulators_dir=self.emulators_dir,
+                offline=True,
+                required_only=required_only,
+            )
+            return {entry["dest"] for entry in manifest["files"]}
+
+        every = names(False)
+        required = names(True)
+        self.assertIn("present_req.bin", every)
+        self.assertIn("present_opt.bin", every)
+        self.assertIn("present_req.bin", required)
+        self.assertNotIn(
+            "present_opt.bin",
+            required,
+            "an optional file reached a manifest built with required_only",
+        )
+
     def test_91_generate_manifest(self):
         """generate_manifest returns valid manifest dict with expected fields."""
         from generate_pack import generate_manifest