diff --git a/src/dexorder/base/fork.py b/src/dexorder/base/fork.py
index a9e5a0f..875a6c9 100644
--- a/src/dexorder/base/fork.py
+++ b/src/dexorder/base/fork.py
@@ -37,7 +37,7 @@ class Fork:
 
     @property
     def parent(self):
-        return self.ancestry[1]
+        return self.ancestry[1] if len(self.ancestry) > 1 else None
 
     def for_height(self, height):
         """ returns a new Fork object for an older block along this fork.  used for root promotion. """
diff --git a/src/dexorder/progressor.py b/src/dexorder/progressor.py
index ebb45a4..61cada6 100644
--- a/src/dexorder/progressor.py
+++ b/src/dexorder/progressor.py
@@ -1,3 +1,4 @@
+import functools
 import logging
 from abc import ABCMeta, abstractmethod
 from typing import Callable, Union
@@ -29,8 +30,11 @@ class BlockProgressor(metaclass=ABCMeta):
 
     def add_event_trigger(self,
             # callback takes either a single event if multi=False, or if multi=True then a list of all events in the processing range
-            callback: Union[Callable[[EventData], Maywaitable[None]],
-                            Callable[[list[EventData]], Maywaitable[None]]],
+            callback: Union[
+                Callable[[EventData], Maywaitable[None]],
+                Callable[[list[EventData]], Maywaitable[None]],
+                Callable[[], Maywaitable[None]],
+            ],
             event: ContractEvents = None,
             log_filter: Union[dict, str] = None,
             *, multi=False):
@@ -39,7 +43,7 @@ class BlockProgressor(metaclass=ABCMeta):
         """
         if log_filter is None and event is not None:
             log_filter = {'topics': [topic(event.abi)]}
-        cb = callback if multi else lambda events: map(cb, events)
+        cb = callback if event is None or multi else functools.partial(map, callback)
         self.events.append((cb, event, log_filter))
 
     @abstractmethod
diff --git a/src/dexorder/runner.py b/src/dexorder/runner.py
index ad5d030..ca5de55 100644
--- a/src/dexorder/runner.py
+++ b/src/dexorder/runner.py
@@ -108,7 +108,7 @@ class BlockStateRunner(BlockProgressor):
                     subscription = await w3ws.eth.subscribe('newHeads')  # the return value of this call is not consistent between anvil/hardhat/rpc.  do not use it.
                     log.debug(f'subscribed to newHeads {subscription}')
                     while self.running:
-                        async for message in w3ws.ws.listen_to_websocket():
+                        async for message in w3ws.ws.process_subscriptions():
                             head = message['result']
                             log.debug(f'detected new block {head["number"]} {hexstr(head["hash"])}')
                             await self.add_head(head["hash"])
@@ -255,7 +255,6 @@ class BlockStateRunner(BlockProgressor):
 
 
     async def handle_head(self, chain, block, w3):
-        print(f'logger {log} {log.name} level {log.level} {logging.DEBUG} {logging.FATAL}')
         log.debug(f'handle_head {block.height} {hexstr(block.hash)}')
         session = None
         batches = []
@@ -275,7 +274,7 @@ class BlockStateRunner(BlockProgressor):
                 log.debug(f'discarded late-arriving head {block}')
             else:
                 batches: list
-                from_height = fork.parent.height
+                from_height = self.state.by_hash[fork.parent].height if fork.parent is not None else fork.height
                 to_height = fork.height
                 if fork.disjoint:
                     batches = await self.get_backfill_batches(from_height, to_height, w3)
@@ -293,8 +292,8 @@ class BlockStateRunner(BlockProgressor):
                             if not config.parallel_logevent_queries:
                                 get_logs = await get_logs
                             batches.append((get_logs, callback, event, log_filter))
-                    for callback in self.postprocess_cbs:
-                        batches.append((None, callback, None, None))
+                for callback in self.postprocess_cbs:
+                    batches.append((None, callback, None, None))
 
                 # set up for callbacks
                 current_block.set(block)