diff --git a/piker/tsp/__init__.py b/piker/tsp/__init__.py
index 17652ee5..9da46591 100644
--- a/piker/tsp/__init__.py
+++ b/piker/tsp/__init__.py
@@ -891,44 +891,49 @@ async def tsdb_backfill(
                 config,
             )
 
-            # tell parent task to continue
-            # TODO: really we'd want this the other way with the
-            # tsdb load happening asap and the since the latest
-            # frame query will normally be the main source of
-            # latency?
-            task_status.started()
-
             tsdb_entry: tuple = await load_tsdb_hist(
                 storage,
                 mkt,
                 timeframe,
             )
 
+        # tell parent task to continue
+        # TODO: really we'd want this the other way with the
+        # tsdb load happening asap and the since the latest
+        # frame query will normally be the main source of
+        # latency?
+        task_status.started()
+
         # NOTE: iabs to start backfilling from, reverse chronological,
         # ONLY AFTER the first history frame has been pushed to
         # mem!
         backfill_gap_from_shm_index: int = shm._first.value + 1
 
-        (
-            mr_start_dt,
-            mr_end_dt,
-        ) = dt_eps
+        # Prepend any tsdb history to the shm buffer which should
+        # now be full of the most recent history pulled from the
+        # backend's last frame.
+        if (
+            dt_eps
+            and tsdb_entry
+        ):
+            # unpack both the latest (gap) backfilled frame dts
+            (
+                mr_start_dt,
+                mr_end_dt,
+            ) = dt_eps
 
-        async with trio.open_nursery() as tn:
+            # AND the tsdb history from (offline) storage)
+            (
+                tsdb_history,
+                first_tsdb_dt,
+                last_tsdb_dt,
+            ) = tsdb_entry
 
-            # Prepend any tsdb history to the shm buffer which should
-            # now be full of the most recent history pulled from the
-            # backend's last frame.
-            if tsdb_entry:
-                (
-                    tsdb_history,
-                    first_tsdb_dt,
-                    last_tsdb_dt,
-                ) = tsdb_entry
+            # if there is a gap to backfill from the first
+            # history frame until the last datum loaded from the tsdb
+            # continue that now in the background
+            async with trio.open_nursery() as tn:
 
-                # if there is a gap to backfill from the first
-                # history frame until the last datum loaded from the tsdb
-                # continue that now in the background
                 bf_done = await tn.start(
                     partial(
                         start_backfill,
@@ -941,8 +946,10 @@ async def tsdb_backfill(
 
                         backfill_from_shm_index=backfill_gap_from_shm_index,
                         backfill_from_dt=mr_start_dt,
+
                         sampler_stream=sampler_stream,
                         backfill_until_dt=last_tsdb_dt,
+
                         storage=storage,
                         write_tsdb=True,
                     )
@@ -1032,11 +1039,11 @@ async def tsdb_backfill(
                     mkt=mkt,
                 ))
 
+            # 2nd nursery END
 
-        # TODO: who would want to?
-        await nulls_detected.wait()
-
-        await bf_done.wait()
+            # TODO: who would want to?
+            await nulls_detected.wait()
+            await bf_done.wait()
         # TODO: maybe start history anal and load missing "history
         # gaps" via backend..