diff --git a/gsrest/db/cassandra.py b/gsrest/db/cassandra.py
index f250356e..cfb0a542 100644
--- a/gsrest/db/cassandra.py
+++ b/gsrest/db/cassandra.py
@@ -187,8 +187,7 @@ def merge_address_txs_subquery_results(
     ]
     results = heapq.nlargest(fetch_size,
                              candidates,
-                             key=partial(transaction_ordering_key,
-                                         tx_id_keys))
+                             key=partial(transaction_ordering_key, tx_id_keys))
 
     border_tx_id = results[-1][tx_id_keys] if results else None
     return results, border_tx_id
@@ -234,6 +233,7 @@ def build_select_address_txs_statement(network: str, node_type: NodeType,
 
 
 class Cassandra:
+
     def eth(func):
 
         def check(*args, **kwargs):
@@ -367,11 +367,23 @@ def load_parameters(self, keyspace):
             "token_config"] = self.load_token_configuration(keyspace)
 
         # check schema for compatibility and set parameter flags
+        keyspace_name = self.get_keyspace_mapping(keyspace, "transformed")
+
+        if keyspace == "eth":
+            query = ("SELECT column_name FROM system_schema.columns "
+                     "WHERE keyspace_name = %s AND "
+                     "table_name = 'block_transactions';")
+            result = self.session.execute(query, (keyspace_name, ))
+            self.parameters[currency]["use_flat_block_txs"] = ("tx_id" in [
+                x["column_name"] for x in result
+            ]) and keyspace == "eth"
+        else:
+            self.parameters[currency]["use_flat_block_txs"] = False
         query = (
             "SELECT column_name FROM system_schema.columns "
             "WHERE keyspace_name = %s AND table_name = 'address_transactions';"
         )
-        keyspace_name = self.get_keyspace_mapping(keyspace, "transformed")
+
         result = self.session.execute(query, (keyspace_name, ))
         self.parameters[currency]["use_legacy_log_index"] = ("log_index" in [
             x["column_name"] for x in result
@@ -729,7 +741,8 @@ async def list_txs_by_node_type(self,
             id=id,
             tx_id_lower_bound=first_tx_id,
             tx_id_upper_bound=upper_bound,
-            is_outgoing=(direction == 'out' if direction is not None else None),
+            is_outgoing=(direction == 'out'
+                         if direction is not None else None),
             include_assets=include_assets,
             page=page,
             fetch_size=fetch_size)
@@ -772,17 +785,20 @@ async def list_block_txs_ids(self, currency, height):
         return [tx.tx_id for tx in result.one()['txs']]
 
     async def list_block_txs_ids_eth(self, currency, height):
-        if height is None:
-            return None
-        height_group = self.get_id_group(currency, height)
-        query = ("SELECT txs FROM block_transactions "
-                 "WHERE block_id_group=%s and block_id=%s")
-        result = await self.execute_async(
-            currency, 'transformed', query,
-            [height_group, int(height)])
-        if one(result) is None:
-            return None
-        return result.one()['txs']
+        if not self.parameters[currency]["use_flat_block_txs"]:
+            if height is None:
+                return None
+            height_group = self.get_id_group(currency, height)
+            query = ("SELECT txs FROM block_transactions "
+                     "WHERE block_id_group=%s and block_id=%s")
+            result = await self.execute_async(
+                currency, 'transformed', query,
+                [height_group, int(height)])
+            if one(result) is None:
+                return None
+            return result.one()['txs']
+        else:
+            return await self.list_block_txs_ids_trx(currency, height)
 
     async def list_block_txs_ids_trx(self, currency, height):
         if height is None:
@@ -1921,19 +1937,19 @@ async def get_id_secondary_group_eth(self, currency, table, id_group):
         return 0 if result is None else \
             result['max_secondary_id']
 
-    async def list_address_txs_ordered(
-            self,
-            network: str,
-            node_type: NodeType,
-            id,
-            tx_id_lower_bound: Optional[int],
-            tx_id_upper_bound: Optional[int],
-            is_outgoing: Optional[bool],
-            include_assets: Sequence[Tuple[str, bool]],
-            page: Optional[int],
-            fetch_size: int,
-            cols: Optional[Sequence[str]] = None,
-            tx_ids: Optional[Sequence[int]] = None):
+    async def list_address_txs_ordered(self,
+                                       network: str,
+                                       node_type: NodeType,
+                                       id,
+                                       tx_id_lower_bound: Optional[int],
+                                       tx_id_upper_bound: Optional[int],
+                                       is_outgoing: Optional[bool],
+                                       include_assets: Sequence[Tuple[str,
+                                                                      bool]],
+                                       page: Optional[int],
+                                       fetch_size: int,
+                                       cols: Optional[Sequence[str]] = None,
+                                       tx_ids: Optional[Sequence[int]] = None):
         """Loads a address transactions in execution order
         it allows to only get out- or incoming transaction or only
         transactions of a certain asset (token), for a given address id
@@ -1973,7 +1989,8 @@ async def list_address_txs_ordered(
 
             item_id_secondary_group = self.sec_in(secondary_id_group)
 
-        directions = [is_outgoing] if is_outgoing is not None else [False, True]
+        directions = [is_outgoing
+                      ] if is_outgoing is not None else [False, True]
         results = []
         """
             Keep retrieving pages until the demanded fetch_size is fulfilled
@@ -2087,7 +2104,8 @@ async def list_txs_by_node_type_eth(self,
             id=address,
             tx_id_lower_bound=first_tx_id,
             tx_id_upper_bound=upper_bound,
-            is_outgoing=(direction == 'out' if direction is not None else None),
+            is_outgoing=(direction == 'out'
+                         if direction is not None else None),
             include_assets=include_assets,
             page=page,
             fetch_size=fetch_size)