diff --git a/swh/storage/migrate_extrinsic_metadata.py b/swh/storage/migrate_extrinsic_metadata.py
--- a/swh/storage/migrate_extrinsic_metadata.py
+++ b/swh/storage/migrate_extrinsic_metadata.py
@@ -1064,7 +1064,35 @@
         if type_ == "dsc":
             assert origin is None
             origins = debian_origins_from_row(row, storage)
-            assert origins, row
+            if hash_to_hex(row["id"]) not in (
+                # Known not to be referenced by any snapshot
+                "09c70e1fe774bce8d19874442f9da0b3fcd4d740",
+                "147fe5dc37eb9d449adddae46230384a94c65d06",
+                "165ac1b0c61f6af73b379e3167c23e8e3b94ab27",
+                "1b1039243b8728148bcb6afc2b087f1ec5411aa9",
+                "1f010d11f10ecb13d93c3b923fc8c8994fd6ac75",
+                "23a059ba95a860e2c479c73703385c86f7156d0e",
+                "2beca1dc7f0ecb0959ced56509c191fb65b79ae3",
+                "3224373eacc16b7a755cf6bd54eb23aa46be8036",
+                "4016b073c53a10af5224d0e2157318e89a17ab0f",
+                "441e0161e5d34652e165b1c30f693825c12f1555",
+                "45f358ea6b4d190565ad95b99ef11cfa95959a6e",
+                "4a35dea5ede1dde20759a0e0ae63221ae3751369",
+                "4cd506fd5cd7406a04296947b0cdbd03a1247972",
+                "4e8b1e719b0e53a7340f5509f434e6583e5e799f",
+                "520d36f3209008fabed70f4e83f7013f6dc2dc2b",
+                "54ceee750aeacca14f9ea52ca4a882e9e3c84b7c",
+                "5924070d614f3a0dd922cbf91910d5aabfe88175",
+                "5d831e2b1d7f2cabb78581b1e5aa23a062ce147d",
+                "63b506fcc2b07d3b7aeea572563a4844210653ef",
+                "69b3c7915fe7301980851946f8f8d32912359443",
+            ) and (
+                # We didn't check which are referenced and which aren't
+                # after this id
+                hash_to_hex(row["id"])
+                < "69b3c7915fe7301980851946f8f8d32912359443"
+            ):
+                assert origins, row
         else:
             origins = [origin]