diff --git a/src/blockchain_utilities/blockchain_export.cpp b/src/blockchain_utilities/blockchain_export.cpp
index 269710ee1..f145bc107 100644
--- a/src/blockchain_utilities/blockchain_export.cpp
+++ b/src/blockchain_utilities/blockchain_export.cpp
@@ -57,6 +57,8 @@ std::string join_set_strings(const std::unordered_set<std::string>& db_types_all
 
 int main(int argc, char* argv[])
 {
+  TRY_ENTRY();
+
   epee::string_tools::set_module_name_and_folder(argv[0]);
 
   std::string default_db_type = "lmdb";
@@ -80,7 +82,7 @@ int main(int argc, char* argv[])
   po::options_description desc_cmd_only("Command line options");
   po::options_description desc_cmd_sett("Command line options and settings options");
   const command_line::arg_descriptor<std::string> arg_output_file = {"output-file", "Specify output file", "", true};
-  const command_line::arg_descriptor<uint32_t> arg_log_level  = {"log-level",  "", log_level};
+  const command_line::arg_descriptor<std::string> arg_log_level  = {"log-level",  "0-4 or categories", ""};
   const command_line::arg_descriptor<uint64_t> arg_block_stop = {"block-stop", "Stop at block number", block_stop};
   const command_line::arg_descriptor<bool>     arg_testnet_on = {
     "testnet"
@@ -124,11 +126,13 @@ int main(int argc, char* argv[])
     return 1;
   }
 
-  log_level    = command_line::get_arg(vm, arg_log_level);
+  mlog_configure(mlog_get_default_log_path("monero-blockchain-export.log"), true);
+  if (!vm["log-level"].defaulted())
+    mlog_set_log(command_line::get_arg(vm, arg_log_level).c_str());
+  else
+    mlog_set_log(std::string(std::to_string(log_level) + ",bcutil:INFO").c_str());
   block_stop = command_line::get_arg(vm, arg_block_stop);
 
-  mlog_configure(mlog_get_default_log_path("monero-blockchain-export.log"), true);
-  mlog_set_log(std::string(std::to_string(log_level) + ",bcutil:INFO").c_str());
   LOG_PRINT_L0("Starting...");
 
   bool opt_testnet = command_line::get_arg(vm, arg_testnet_on);
@@ -226,4 +230,7 @@ int main(int argc, char* argv[])
   }
   CHECK_AND_ASSERT_MES(r, false, "Failed to export blockchain raw data");
   LOG_PRINT_L0("Blockchain raw data exported OK");
+  return 0;
+
+  CATCH_ENTRY("Export error", 1);
 }
diff --git a/src/blockchain_utilities/blockchain_import.cpp b/src/blockchain_utilities/blockchain_import.cpp
index 83fd6fb20..b2c217ca1 100644
--- a/src/blockchain_utilities/blockchain_import.cpp
+++ b/src/blockchain_utilities/blockchain_import.cpp
@@ -596,6 +596,8 @@ int import_from_file(FakeCore& simple_core, const std::string& import_file_path,
 
 int main(int argc, char* argv[])
 {
+  TRY_ENTRY();
+
   epee::string_tools::set_module_name_and_folder(argv[0]);
 
   std::string default_db_type = "lmdb";
@@ -622,7 +624,7 @@ int main(int argc, char* argv[])
   po::options_description desc_cmd_only("Command line options");
   po::options_description desc_cmd_sett("Command line options and settings options");
   const command_line::arg_descriptor<std::string> arg_input_file = {"input-file", "Specify input file", "", true};
-  const command_line::arg_descriptor<uint32_t> arg_log_level   = {"log-level",  "", log_level};
+  const command_line::arg_descriptor<std::string> arg_log_level   = {"log-level",  "0-4 or categories", ""};
   const command_line::arg_descriptor<uint64_t> arg_block_stop  = {"block-stop", "Stop at block number", block_stop};
   const command_line::arg_descriptor<uint64_t> arg_batch_size  = {"batch-size", "", db_batch_size};
   const command_line::arg_descriptor<uint64_t> arg_pop_blocks  = {"pop-blocks", "Remove blocks from end of blockchain", num_blocks};
@@ -682,7 +684,6 @@ int main(int argc, char* argv[])
   if (! r)
     return 1;
 
-  log_level     = command_line::get_arg(vm, arg_log_level);
   opt_verify    = command_line::get_arg(vm, arg_verify);
   opt_batch     = command_line::get_arg(vm, arg_batch);
   opt_resume    = command_line::get_arg(vm, arg_resume);
@@ -725,7 +726,11 @@ int main(int argc, char* argv[])
   db_arg_str = command_line::get_arg(vm, arg_database);
 
   mlog_configure(mlog_get_default_log_path("monero-blockchain-import.log"), true);
-  mlog_set_log(std::string(std::to_string(log_level) + ",bcutil:INFO").c_str());
+  if (!vm["log-level"].defaulted())
+    mlog_set_log(command_line::get_arg(vm, arg_log_level).c_str());
+  else
+    mlog_set_log(std::string(std::to_string(log_level) + ",bcutil:INFO").c_str());
+
   MINFO("Starting...");
 
   boost::filesystem::path fs_import_file_path;
@@ -852,4 +857,6 @@ int main(int argc, char* argv[])
   // calls delete on its BlockchainDB derived class' object, which closes its
   // files.
   return 0;
+
+  CATCH_ENTRY("Import error", 1);
 }
diff --git a/src/cryptonote_core/blockchain.cpp b/src/cryptonote_core/blockchain.cpp
index f49050918..0713274a6 100644
--- a/src/cryptonote_core/blockchain.cpp
+++ b/src/cryptonote_core/blockchain.cpp
@@ -4016,7 +4016,7 @@ void Blockchain::cancel()
 static const char expected_block_hashes_hash[] = "23d8a8c73de7b2383c72a016d9a6034e69d62dd48077d1c414e064ceab6daa94";
 void Blockchain::load_compiled_in_block_hashes()
 {
-  if (m_fast_sync && get_blocks_dat_start(m_testnet) != nullptr)
+  if (m_fast_sync && get_blocks_dat_start(m_testnet) != nullptr && get_blocks_dat_size(m_testnet) > 0)
   {
     MINFO("Loading precomputed blocks (" << get_blocks_dat_size(m_testnet) << " bytes)");