diff --git a/requirements.txt b/requirements.txt
index facc3d7..edda26c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -15,5 +15,6 @@ async-lru
 eth-bloom
 python-dateutil
 eth_abi
+eth_utils
 pdpyras  # pagerduty
 numpy
diff --git a/src/dexorder/blocks.py b/src/dexorder/blocks.py
index 6cd228a..c2b723c 100644
--- a/src/dexorder/blocks.py
+++ b/src/dexorder/blocks.py
@@ -149,7 +149,10 @@ def promotion_height(chain: Blockchain=None, latest_height: int=None):
     if chain is None:
         chain = current_chain.get()
     if latest_height is None:
-        latest_height = latest_block.get(chain.id).height
+        block = latest_block.get(chain.id)
+        if block is None:
+            return 0
+        latest_height = block.height
         if latest_height is None:
             return 0
     confirm_offset = config.confirms if config.confirms is not None else chain.confirms
diff --git a/src/dexorder/configuration/schema.py b/src/dexorder/configuration/schema.py
index fc56f3f..9feecb6 100644
--- a/src/dexorder/configuration/schema.py
+++ b/src/dexorder/configuration/schema.py
@@ -26,7 +26,7 @@ class Config:
     concurrent_rpc_connections: int = 4
     parallel_logevent_queries: bool = True
     polling: float = 0  # seconds between queries for a new block.  0 disables polling and uses a websocket subscription on ws_url instead
-    backfill: int = 0  # if not 0, then runner will initialize an empty database by backfilling from the given block height
+    backfill: int = 0  # if not 0, then runner will initialize an empty database by backfilling from the given block height. Use negative numbers to indicate a number of blocks before the present.
 
     account: Optional[str] = None # may be a private key or an account alias
     accounts: Optional[dict[str,str]] = field(default_factory=dict) # account aliases
diff --git a/src/dexorder/runner.py b/src/dexorder/runner.py
index d1b4685..1e9a352 100644
--- a/src/dexorder/runner.py
+++ b/src/dexorder/runner.py
@@ -17,6 +17,7 @@ from dexorder.blockstate import BlockState, current_blockstate
 from dexorder.blockstate.branch import Branch
 from dexorder.blockstate.diff import DiffEntryItem
 from dexorder.blockstate.fork import current_fork, Fork
+from dexorder.contract.dexorder import get_dexorder_contract, get_factory_contract, get_vault_init_code_hash
 from dexorder.progressor import BlockProgressor
 from dexorder.transactions import create_and_send_transactions
 from dexorder.util import hexstr, hexbytes
@@ -217,9 +218,29 @@ class BlockStateRunner(BlockProgressor):
             w3 = current_w3.get()
             chain = current_chain.get()
             assert chain.id == await w3.eth.chain_id
+
+            log.info(f'''
+    Chain    {chain}
+    Factory  {get_factory_contract().address}
+    Dexorder {get_dexorder_contract().address}
+    VICH     {hexstr(get_vault_init_code_hash())}''')
+
+            # backfill
+            if self.state is None and config.backfill != 0:
+                if config.backfill > 0:
+                    height = config.backfill
+                else:
+                    cur = await w3.eth.get_block_number()
+                    height = cur + config.backfill if config.backfill < 0 else cur
+                block = await get_block(height)
+                self.set_latest_block(block)
+                self.new_head_event.set()
+                log.info(f'Backfilling from block {block}')
+
+            # main run loop
             while self.running:
                 try:
-                    await asyncio.wait_for(self.new_head_event.wait(), timeout=1)  # todo configure
+                    await asyncio.wait_for(self.new_head_event.wait(), timeout=1)
                 except TimeoutError:
                     # DISABLED. See note on handle_time_tick()
                     # if fork is not None: