diff --git a/piker/data/feed.py b/piker/data/feed.py
index 8c88f04b..a95b87b4 100644
--- a/piker/data/feed.py
+++ b/piker/data/feed.py
@@ -31,6 +31,7 @@ from typing import (
     AsyncIterator, Optional,
     Generator,
     Awaitable,
+    TYPE_CHECKING,
 )
 
 import trio
@@ -74,6 +75,8 @@ from ..brokers._util import (
     DataUnavailable,
 )
 
+if TYPE_CHECKING:
+    from .marketstore import Storage
 
 log = get_logger(__name__)
 
@@ -234,6 +237,7 @@ async def start_backfill(
     shm: ShmArray,
 
     last_tsdb_dt: Optional[datetime] = None,
+    storage: Optional[Storage] = None,
 
     task_status: TaskStatus[trio.CancelScope] = trio.TASK_STATUS_IGNORED,
 
@@ -520,6 +524,7 @@ async def start_backfill(
                             break
 
                     to_push, start_dt, end_dt = frames.pop(epoch)
+                    ln = len(to_push)
 
                     # bail gracefully on shm allocation overrun/full condition
                     try:
@@ -528,19 +533,27 @@ async def start_backfill(
                         log.info(
                             f'Shm buffer overrun on: {start_dt} -> {end_dt}?'
                         )
-                        # await tractor.breakpoint()
                         break
 
                     log.info(
-                        f'Shm pushed {len(to_push)} frame:\n'
+                        f'Shm pushed {ln} frame:\n'
                         f'{start_dt} -> {end_dt}'
                     )
-
                     # keep track of most recent "prepended" ``start_dt``
                     # both for detecting gaps and ensuring async
                     # frame-result order.
                     earliest_end_dt = start_dt
 
+                    if storage is not None:
+                        log.info(
+                            f'Writing {ln} frame to storage:\n'
+                            f'{start_dt} -> {end_dt}'
+                        )
+                        await storage.write_ohlcv(
+                            f'{bfqsn}.{mod.name}',  # lul..
+                            to_push,
+                        )
+
                 # TODO: can we only trigger this if the respective
                 # history in "in view"?!?
                 # XXX: extremely important, there can be no checkpoints
@@ -609,7 +622,7 @@ async def manage_history(
             # shm backfiller approach below.
 
             # start history anal and load missing new data via backend.
-            series, first_dt, last_dt = await storage.load(fqsn)
+            series, _, last_tsdb_dt = await storage.load(fqsn)
 
             broker, symbol, expiry = unpack_fqsn(fqsn)
             (
@@ -623,7 +636,8 @@ async def manage_history(
                     mod,
                     bfqsn,
                     shm,
-                    last_tsdb_dt=last_dt,
+                    last_tsdb_dt=last_tsdb_dt,
+                    storage=storage,
                 )
             )
 
@@ -644,8 +658,10 @@ async def manage_history(
             # do diff against last start frame of history and only fill
             # in from the tsdb an allotment that allows for most recent
             # to be loaded into mem *before* tsdb data.
-            if last_dt:
-                dt_diff_s = (latest_start_dt - last_dt).seconds
+            if last_tsdb_dt:
+                dt_diff_s = (
+                    latest_start_dt - last_tsdb_dt
+                ).seconds
             else:
                 dt_diff_s = 0
 
@@ -674,7 +690,7 @@ async def manage_history(
                     field_map=marketstore.ohlc_key_map,
                 )
 
-                # load as much from storage into shm as spacec will
+                # load as much from storage into shm as space will
                 # allow according to user's shm size settings.
                 count = 0
                 end = fastest['Epoch'][0]
@@ -699,15 +715,11 @@ async def manage_history(
                         prepend=True,
                         # update_first=False,
                         # start=prepend_start,
-                        field_map={
-                            'Epoch': 'time',
-                            'Open': 'open',
-                            'High': 'high',
-                            'Low': 'low',
-                            'Close': 'close',
-                            'Volume': 'volume',
-                        },
+                        field_map=marketstore.ohlc_key_map,
                     )
+
+                    # manually trigger step update to update charts/fsps
+                    # which need an incremental update.
                     for delay_s in sampler.subscribers:
                         await broadcast(delay_s)