diff --git a/scripts/generate_db.py b/scripts/generate_db.py
index a3afdc1f..53d4d48c 100644
--- a/scripts/generate_db.py
+++ b/scripts/generate_db.py
@@ -437,6 +437,15 @@ def _collect_all_aliases(files: dict) -> dict:
                         sha1 = file_entry.get("sha1", "")
                         md5 = file_entry.get("md5", "")
 
+                        # A zipped_file entry verifies a ROM INSIDE the
+                        # archive, so its hash describes the member and not
+                        # the file the name designates. Registering the name
+                        # against that hash made d2fdc.zip an alias of a
+                        # loose 256-byte state-machine-16.rom, which three
+                        # platforms were then served in place of the archive.
+                        if file_entry.get("zipped_file"):
+                            continue
+
                         matched = None
                         if sha1 and sha1 in files:
                             matched = sha1
diff --git a/tests/test_shipped_content.py b/tests/test_shipped_content.py
index dd7af502..118a0c3e 100644
--- a/tests/test_shipped_content.py
+++ b/tests/test_shipped_content.py
@@ -17,6 +17,8 @@ from __future__ import annotations
 
 import hashlib
 import json
+import os
+import re
 import sys
 import unittest
 import zipfile
@@ -182,5 +184,39 @@ class ProfileContradictionsAreKnown(unittest.TestCase):
         )
 
 
+class ArchiveNamesDesignateArchives(unittest.TestCase):
+    """A name ending in .zip must not designate a loose file.
+
+    The alias collector matched a platform entry's name against the SHA1 its
+    md5 pointed at without looking at zipped_file, and a zipped_file md5 is
+    the member's, not the container's. d2fdc.zip became an alias of a loose
+    256-byte state-machine-16.rom, and three platforms were served that ROM
+    where they had asked for the archive.
+    """
+
+    def test_no_archive_name_resolves_to_a_loose_file(self):
+        database = ROOT / "database.json"
+        if not database.is_file():
+            self.skipTest("database.json not built")
+        db = common.load_database(str(database))
+        loose = []
+        for name, ids in db["indexes"]["by_name"].items():
+            if not name.lower().endswith(".zip"):
+                continue
+            for sha1 in ids:
+                path = db["files"].get(sha1, {}).get("path", "")
+                base = os.path.basename(path).lower()
+                # <name>.zip, or the repo's variant form <name>.zip.<md5prefix>
+                if not re.match(r".*\.zip(\.[0-9a-f]{6,})?$", base):
+                    loose.append(f"{name} -> {path}")
+        self.assertLessEqual(
+            len(loose),
+            1,
+            "an archive name designates a loose file; the only accepted case is "
+            "ngpc.zip, whose md5 RetroDECK itself declares against the loose "
+            f"Neo Geo Pocket Color BIOS:\n  " + "\n  ".join(sorted(loose)),
+        )
+
+
 if __name__ == "__main__":
     unittest.main()