diff --git a/src/cryptonote_core/blockchain.cpp b/src/cryptonote_core/blockchain.cpp
index 1fda54f34..504713daf 100644
--- a/src/cryptonote_core/blockchain.cpp
+++ b/src/cryptonote_core/blockchain.cpp
@@ -1184,7 +1184,7 @@ bool Blockchain::validate_miner_transaction(const block& b, size_t cumulative_bl
     }
   }
 
-  std::vector<size_t> last_blocks_weights;
+  std::vector<uint64_t> last_blocks_weights;
   get_last_n_blocks_weights(last_blocks_weights, CRYPTONOTE_REWARD_BLOCKS_WINDOW);
   if (!get_block_reward(epee::misc_utils::median(last_blocks_weights), cumulative_block_weight, already_generated_coins, base_reward, version))
   {
@@ -1219,7 +1219,7 @@ bool Blockchain::validate_miner_transaction(const block& b, size_t cumulative_bl
 }
 //------------------------------------------------------------------
 // get the block weights of the last <count> blocks, and return by reference <sz>.
-void Blockchain::get_last_n_blocks_weights(std::vector<size_t>& weights, size_t count) const
+void Blockchain::get_last_n_blocks_weights(std::vector<uint64_t>& weights, size_t count) const
 {
   LOG_PRINT_L3("Blockchain::" << __func__);
   CRITICAL_REGION_LOCAL(m_blockchain_lock);
@@ -3079,7 +3079,7 @@ uint64_t Blockchain::get_dynamic_base_fee_estimate(uint64_t grace_blocks) const
     grace_blocks = CRYPTONOTE_REWARD_BLOCKS_WINDOW - 1;
 
   const uint64_t min_block_weight = get_min_block_weight(version);
-  std::vector<size_t> weights;
+  std::vector<uint64_t> weights;
   get_last_n_blocks_weights(weights, CRYPTONOTE_REWARD_BLOCKS_WINDOW - grace_blocks);
   weights.reserve(grace_blocks);
   for (size_t i = 0; i < grace_blocks; ++i)
@@ -3697,7 +3697,7 @@ bool Blockchain::update_next_cumulative_weight_limit(uint64_t *long_term_effecti
 
   if (hf_version < HF_VERSION_LONG_TERM_BLOCK_WEIGHT)
   {
-    std::vector<size_t> weights;
+    std::vector<uint64_t> weights;
     get_last_n_blocks_weights(weights, CRYPTONOTE_REWARD_BLOCKS_WINDOW);
     m_current_block_cumul_weight_median = epee::misc_utils::median(weights);
     long_term_block_weight = weights.back();
diff --git a/src/cryptonote_core/blockchain.h b/src/cryptonote_core/blockchain.h
index 175d93671..a79ff22a1 100644
--- a/src/cryptonote_core/blockchain.h
+++ b/src/cryptonote_core/blockchain.h
@@ -1262,7 +1262,7 @@ namespace cryptonote
      * @param sz return-by-reference the list of weights
      * @param count the number of blocks to get weights for
      */
-    void get_last_n_blocks_weights(std::vector<size_t>& weights, size_t count) const;
+    void get_last_n_blocks_weights(std::vector<uint64_t>& weights, size_t count) const;
 
     /**
      * @brief checks if a transaction is unlocked (its outputs spendable)
diff --git a/src/cryptonote_core/cryptonote_core.cpp b/src/cryptonote_core/cryptonote_core.cpp
index 0d32c3084..04e6ea42d 100644
--- a/src/cryptonote_core/cryptonote_core.cpp
+++ b/src/cryptonote_core/cryptonote_core.cpp
@@ -1803,7 +1803,7 @@ namespace cryptonote
     for (size_t n = 0; n < sizeof(seconds)/sizeof(seconds[0]); ++n)
     {
       unsigned int b = 0;
-      for (time_t ts: timestamps) b += ts >= now - seconds[n];
+      for (time_t ts: timestamps) b += ts >= (time_t)(now - seconds[n]);
       const double p = probability(b, seconds[n] / DIFFICULTY_TARGET_V2);
       MDEBUG("blocks in the last " << seconds[n] / 60 << " minutes: " << b << " (probability " << p << ")");
       if (p < threshold)
diff --git a/tests/core_tests/v2_tests.h b/tests/core_tests/v2_tests.h
index ecb23818c..cd2bcb839 100644
--- a/tests/core_tests/v2_tests.h
+++ b/tests/core_tests/v2_tests.h
@@ -81,7 +81,7 @@ template<>
 struct get_test_options<gen_v2_tx_validation_base> {
   const std::pair<uint8_t, uint64_t> hard_forks[3] = {std::make_pair(1, 0), std::make_pair(2, 1), std::make_pair(0, 0)};
   const cryptonote::test_options test_options = {
-    hard_forks
+    hard_forks, 0
   };
 };