diff --git a/.github/workflows/dump-refresh.yml b/.github/workflows/dump-refresh.yml
index edc2a9d..a35019a 100644
--- a/.github/workflows/dump-refresh.yml
+++ b/.github/workflows/dump-refresh.yml
@@ -27,7 +27,7 @@ jobs:
     runs-on: ubuntu-latest
     # Well under GitHub's 6h ceiling, which reports an over-run as
     # "cancelled" rather than failed and so hides the breakage.
-    timeout-minutes: 330
+    timeout-minutes: 355
     env:
       TECHAPI_WRITE_TOKEN: ${{ secrets.TECHENGINEBOT_TOKEN || secrets.TECHAPI_TOKEN }}
       # seed/validate/dump read the data tree from here.
@@ -91,7 +91,7 @@ jobs:
           path: ./techapi
           token: ${{ env.TECHAPI_WRITE_TOKEN }}
           branch: dump-refresh/${{ steps.meta.outputs.date }}
-          base: main
+          base: develop
           add-paths: |
             site/public/v1
             site/public/openapi.json
diff --git a/app/dump.py b/app/dump.py
index 01445c8..c20761c 100644
--- a/app/dump.py
+++ b/app/dump.py
@@ -57,8 +57,15 @@ def resolve_collections(exclude: list[str] | None = None) -> list[str]:
 
 
 def _write_json(path: Path, data: object) -> None:
-    path.parent.mkdir(parents=True, exist_ok=True)
-    path.write_text(json.dumps(data, indent=2, ensure_ascii=False) + "\n", encoding="utf-8")
+    text = json.dumps(data, indent=2, ensure_ascii=False) + "\n"
+    # Leave identical pages untouched: rewriting ~1M unchanged files resets
+    # their mtimes, and git then rehashes the whole tree when committing.
+    try:
+        if path.read_text(encoding="utf-8") == text:
+            return
+    except FileNotFoundError:
+        path.parent.mkdir(parents=True, exist_ok=True)
+    path.write_text(text, encoding="utf-8")
 
 
 def _fetch_all(client: TestClient, resource: str) -> tuple[int, list[dict[str, Any]]]: