diff --git a/Abe/DataStore.py b/Abe/DataStore.py
index 29fa28a2..9604601a 100644
--- a/Abe/DataStore.py
+++ b/Abe/DataStore.py
@@ -2361,7 +2361,7 @@ def offer_existing_block(store, hash, chain_id):
                    block_total_satoshis, block_satoshi_seconds,
                    block_total_ss
               FROM block
-             WHERE block_hash = ?
+             WHERE block_hash = (_binary ?)
         """, (store.hashin(hash),))
 
         if not block_row: