diff --git a/src/currency_core/blockchain_storage.cpp b/src/currency_core/blockchain_storage.cpp
index 169868f9..f5674558 100644
--- a/src/currency_core/blockchain_storage.cpp
+++ b/src/currency_core/blockchain_storage.cpp
@@ -5050,7 +5050,8 @@ bool blockchain_storage::prevalidate_block(const block& bl)
     return true;
   if (bl.major_version != CURRENT_BLOCK_MAJOR_VERSION)
   {
-    LOG_ERROR("Failed to prevalidate_block: " << get_block_hash(bl) << ENDL << obj_to_json_str(bl));
+    LOG_ERROR("prevalidation failed for block " << get_block_hash(bl) << ": major block version " << static_cast<size_t>(bl.major_version) << " is incorrect, " << CURRENT_BLOCK_MAJOR_VERSION << " is expected" << ENDL
+      << obj_to_json_str(bl));
     return false;
   }
   return true;
diff --git a/src/currency_core/currency_format_utils_transactions.cpp b/src/currency_core/currency_format_utils_transactions.cpp
index 3f052373..f78ebf16 100644
--- a/src/currency_core/currency_format_utils_transactions.cpp
+++ b/src/currency_core/currency_format_utils_transactions.cpp
@@ -48,7 +48,7 @@ namespace currency
   //---------------------------------------------------------------
   uint64_t get_tx_max_unlock_time(const transaction& tx)
   {
-    // etc_tx_details_expiration_time have priority over etc_tx_details_expiration_time2
+    // etc_tx_details_unlock_time have priority over etc_tx_details_unlock_time2
     uint64_t v = get_tx_x_detail<etc_tx_details_unlock_time>(tx);
     if (v)
       return v;
diff --git a/src/stratum/stratum_server.cpp b/src/stratum/stratum_server.cpp
index ccb86b27..586d5e09 100644
--- a/src/stratum/stratum_server.cpp
+++ b/src/stratum/stratum_server.cpp
@@ -80,7 +80,7 @@ namespace
 #define HR_TO_STREAM_IN_MHS_3P(hr) std::fixed << std::setprecision(3) << hr / 1000000.0
 
 // debug stuff
-#define DBG_NETWORK_DIFFICULTY 0 // if non-zero: use this value as net difficulty when checking shares (useful for debugging on testnet, recommended value is 1600000000ull)
+#define DBG_NETWORK_DIFFICULTY 0 // if non-zero: use this value as net difficulty when checking shares (useful for debugging on testnet, recommended value is 3000000000ull)
 #define DBG_CORE_ALWAYS_SYNCRONIZED 0 // if set to 1: allows the server to start even if the core is not syncronized, useful for debugging with --offline-mode
 #define STRINGIZE_DETAIL(x) #x
 #define STRINGIZE(x) STRINGIZE_DETAIL(x)