diff --git a/libraries/chain/assert_evaluator.cpp b/libraries/chain/assert_evaluator.cpp
index c805280b..e8cf935e 100644
--- a/libraries/chain/assert_evaluator.cpp
+++ b/libraries/chain/assert_evaluator.cpp
@@ -41,7 +41,7 @@ struct predicate_evaluator
    }
    void operator()( const block_id_predicate& p )const
    {
-      FC_ASSERT( block_summary_id_type( block_header::num_from_id( p.id ) )(db).block_id == p.id );
+      FC_ASSERT( block_summary_id_type( block_header::num_from_id( p.id ) & 0xffff )(db).block_id == p.id );
    }
 };
 
diff --git a/libraries/chain/db_block.cpp b/libraries/chain/db_block.cpp
index 5adba8a5..afa98823 100644
--- a/libraries/chain/db_block.cpp
+++ b/libraries/chain/db_block.cpp
@@ -524,6 +524,7 @@ processed_transaction database::_apply_transaction(const signed_transaction& trx
          // integer that satisfies (a) and (b); for x1, the next
          // largest integer that satisfies (a), does not satisfy (b).
          //
+         /**
          int64_t N = head_block_num();
          int64_t a = N & 0xFFFF;
          int64_t r = trx.ref_block_num;
@@ -546,8 +547,9 @@ processed_transaction database::_apply_transaction(const signed_transaction& trx
          {
             ref_block_height = uint32_t( x0 );
          }
+         */
 
-         const auto& tapos_block_summary = block_summary_id_type( ref_block_height )(*this);
+         const auto& tapos_block_summary = block_summary_id_type( trx.ref_block_num )(*this);
 
          //This is the signature check for transactions with relative expiration.
          if( !(skip & skip_transaction_signatures) )
@@ -652,11 +654,11 @@ const witness_object& database::validate_block_header( uint32_t skip, const sign
 
 void database::create_block_summary(const signed_block& next_block)
 {
-   const auto& sum = create<block_summary_object>( [&](block_summary_object& p) {
+   block_summary_id_type sid(next_block.block_num() & 0xffff );
+   modify( sid(*this), [&](block_summary_object& p) {
          p.block_id = next_block.id();
          p.timestamp = next_block.timestamp;
    });
-   FC_ASSERT( sum.id.instance() == next_block.block_num(), "", ("summary.id",sum.id)("next.block_num",next_block.block_num()) );
 }
 
 void database::add_checkpoints( const flat_map<uint32_t,block_id_type>& checkpts )
diff --git a/libraries/chain/db_init.cpp b/libraries/chain/db_init.cpp
index ffd928a3..287a810e 100644
--- a/libraries/chain/db_init.cpp
+++ b/libraries/chain/db_init.cpp
@@ -214,6 +214,9 @@ void database::init_genesis(const genesis_state_type& genesis_state)
 
    transaction_evaluation_state genesis_eval_state(this);
 
+   flat_index<block_summary_object>& bsi = get_mutable_index_type< flat_index<block_summary_object> >(); 
+   bsi.resize(0xffff+1);
+
    // Create blockchain accounts
    fc::ecc::private_key null_private_key = fc::ecc::private_key::regenerate(fc::sha256::hash(string("null_key")));
    create<account_balance_object>([](account_balance_object& b) {
diff --git a/libraries/db/include/graphene/db/flat_index.hpp b/libraries/db/include/graphene/db/flat_index.hpp
index 2df5a23c..06eb3826 100644
--- a/libraries/db/include/graphene/db/flat_index.hpp
+++ b/libraries/db/include/graphene/db/flat_index.hpp
@@ -105,6 +105,12 @@ namespace graphene { namespace db {
 
          size_t size()const{ return _objects.size(); }
 
+         void resize( uint32_t s ) { 
+            _objects.resize(s); 
+            for( uint32_t i = 0; i < s; ++i )
+               _objects[i].id = object_id_type(object_type::space_id,object_type::type_id,i);
+         }
+
       private:
          vector< T > _objects;
    };