diff --git a/src/blockchain_db/lmdb/db_lmdb.cpp b/src/blockchain_db/lmdb/db_lmdb.cpp
index 747d30cf8..963f55790 100644
--- a/src/blockchain_db/lmdb/db_lmdb.cpp
+++ b/src/blockchain_db/lmdb/db_lmdb.cpp
@@ -4434,6 +4434,9 @@ void BlockchainLMDB::migrate_3_4()
         result = mdb_cursor_open(txn, o_block_info, &c_old);
         if (result)
           throw0(DB_ERROR(lmdb_error("Failed to open a cursor for block_info: ", result).c_str()));
+        result = mdb_cursor_open(txn, m_blocks, &c_blocks);
+        if (result)
+          throw0(DB_ERROR(lmdb_error("Failed to open a cursor for blocks: ", result).c_str()));
         if (!i) {
           MDB_stat db_stat;
           result = mdb_stat(txn, m_block_info, &db_stats);
@@ -4462,8 +4465,9 @@ void BlockchainLMDB::migrate_3_4()
       // get block major version to determine which rule is in place
       if (!past_long_term_weight)
       {
-        MDB_val kb, vb;
-        result = mdb_cursor_get(c_blocks, &k, &v, MDB_NEXT);
+        MDB_val_copy<uint64_t> kb(bi.bi_height);
+        MDB_val vb;
+        result = mdb_cursor_get(c_blocks, &kb, &vb, MDB_SET);
         if (result)
           throw0(DB_ERROR(lmdb_error("Failed to query m_blocks: ", result).c_str()));
         if (vb.mv_size == 0)
diff --git a/src/cryptonote_core/blockchain.cpp b/src/cryptonote_core/blockchain.cpp
index 7b1f750db..eedce6d23 100644
--- a/src/cryptonote_core/blockchain.cpp
+++ b/src/cryptonote_core/blockchain.cpp
@@ -504,6 +504,8 @@ bool Blockchain::init(BlockchainDB* db, const network_type nettype, bool offline
   {
     m_long_term_block_weights.push_front(db_height - 1 - m_long_term_block_weights.size());
   }
+  if (!m_long_term_block_weights.empty())
+    m_long_term_block_weights.pop_back();
 
   update_next_cumulative_weight_limit();
   return true;