diff --git a/src/backend/services/computer_file_copy_service.py b/src/backend/services/computer_file_copy_service.py
index b705a6b1..5bdadf2c 100644
--- a/src/backend/services/computer_file_copy_service.py
+++ b/src/backend/services/computer_file_copy_service.py
@@ -714,6 +714,26 @@ def resolve_file_copy_blob_info(
 
     blob_key = _first_text_value(concept_id, "#V#has_blob_key")
     if not blob_key:
+        # Early Jira attachment imports persisted complete blob attributes but
+        # could omit both the format marker and blob text relations. Preserve
+        # canonical text precedence; this only recovers that legacy format.
+        if (
+            attrs.get("source_system") == "jira_attachment"
+            and isinstance(attrs.get("blob_key"), str)
+            and attrs["blob_key"].strip()
+            and attrs.get("blob_backend")
+            and attrs.get("sha256")
+            and isinstance(attrs.get("size_bytes"), int)
+        ):
+            return FileCopyBlobInfo(
+                concept_id=concept_id,
+                blob_key=attrs["blob_key"],
+                blob_backend=attrs["blob_backend"],
+                blob_uri=attrs.get("blob_uri"),
+                content_type=attrs.get("content_type"),
+                original_filename=attrs.get("original_filename"),
+                size_bytes=attrs["size_bytes"],
+            )
         return None
 
     blob_backend = _first_text_value(concept_id, "#V#has_blob_backend")
diff --git a/tests/backend/test_file_copy_retrieval_service.py b/tests/backend/test_file_copy_retrieval_service.py
index 2f79db6f..a0d384c3 100644
--- a/tests/backend/test_file_copy_retrieval_service.py
+++ b/tests/backend/test_file_copy_retrieval_service.py
@@ -203,3 +203,83 @@ def get_bytes(self, key):
 
     assert result["success"] is True
     assert result["data"] == b"team hello!!"
+
+
+def test_legacy_jira_attributes_recover_without_widening_access(monkeypatch):
+    from src.backend.services import computer_file_copy_service as svc
+
+    attrs = {
+        "source_system": "jira_attachment",
+        "blob_key": "imports/legacy/file.pdf",
+        "blob_backend": "s3",
+        "sha256": "a" * 64,
+        "size_bytes": 3,
+        "content_type": "application/pdf",
+        "original_filename": "file.pdf",
+        "user_concept_id": "#V#owner",
+    }
+    doc = {
+        "concept_id": "#V#legacy_file",
+        "attributes": attrs,
+        "relationships": {"#V#specific_to_user": ["#V#owner"]},
+    }
+    monkeypatch.setattr(svc, "_load_file_copy_concept_doc", lambda **kw: doc)
+    monkeypatch.setattr(svc, "_first_text_value", lambda *a: None)
+    reads = []
+
+    class Store:
+        def get_bytes(self, key):
+            reads.append(key)
+            return b"pdf"
+
+    monkeypatch.setattr(
+        "src.backend.services.blob_store.get_blob_store_from_env", lambda: Store()
+    )
+    denied = svc.fetch_file_copy_bytes(
+        file_copy_concept_id=doc["concept_id"], user_concept_id="#V#other"
+    )
+    assert denied["success"] is False
+    assert reads == []
+    result = svc.fetch_file_copy_bytes(
+        file_copy_concept_id=doc["concept_id"], user_concept_id="#V#owner"
+    )
+    assert result["success"] and result["data"] == b"pdf"
+    assert reads == ["imports/legacy/file.pdf"]
+    assert result["info"].original_filename == "file.pdf"
+
+
+def test_legacy_jira_recovery_preserves_text_precedence_and_other_formats(monkeypatch):
+    from src.backend.services import computer_file_copy_service as svc
+
+    doc = {
+        "attributes": {
+            "source_system": "jira_attachment",
+            "blob_key": "old-key",
+            "blob_backend": "s3",
+            "sha256": "a" * 64,
+            "size_bytes": 3,
+        }
+    }
+    monkeypatch.setattr(
+        svc,
+        "_first_text_value",
+        lambda cid, pred: "canonical-key" if pred == "#V#has_blob_key" else None,
+    )
+    assert (
+        svc.resolve_file_copy_blob_info(
+            file_copy_concept_id="#V#file", concept_doc=doc
+        ).blob_key
+        == "canonical-key"
+    )
+    monkeypatch.setattr(svc, "_first_text_value", lambda *a: None)
+    doc["attributes"]["source_system"] = "unrelated"
+    assert (
+        svc.resolve_file_copy_blob_info(file_copy_concept_id="#V#file", concept_doc=doc)
+        is None
+    )
+    doc["attributes"]["source_system"] = "jira_attachment"
+    del doc["attributes"]["blob_key"]
+    assert (
+        svc.resolve_file_copy_blob_info(file_copy_concept_id="#V#file", concept_doc=doc)
+        is None
+    )