diff --git a/src/monero_headers.h b/src/monero_headers.h
index baf4a9c..0cc2a7c 100644
--- a/src/monero_headers.h
+++ b/src/monero_headers.h
@@ -9,8 +9,8 @@
 #define BLOCKCHAIN_DB DB_LMDB
 
 
-#define UNSIGNED_TX_PREFIX "Monero unsigned tx set\002"
-#define SIGNED_TX_PREFIX "Monero signed tx set\002"
+#define UNSIGNED_TX_PREFIX "Monero unsigned tx set\003"
+#define SIGNED_TX_PREFIX "Monero signed tx set\003"
 #define KEY_IMAGE_EXPORT_FILE_MAGIC "Monero key image export\002"
 #define OUTPUT_EXPORT_FILE_MAGIC "Monero output export\003"
 
diff --git a/src/page.h b/src/page.h
index 00dda9e..92c3fc3 100644
--- a/src/page.h
+++ b/src/page.h
@@ -1513,6 +1513,8 @@ public:
 
         const size_t magiclen = strlen(UNSIGNED_TX_PREFIX);
 
+        string data_prefix = xmreg::make_printable(decoded_raw_tx_data.substr(0, magiclen));
+
         bool unsigned_tx_given {false};
 
         if (strncmp(decoded_raw_tx_data.c_str(), UNSIGNED_TX_PREFIX, magiclen) == 0)
@@ -1525,6 +1527,7 @@ public:
                 {"testnet"              , testnet},
                 {"unsigned_tx_given"    , unsigned_tx_given},
                 {"have_raw_tx"          , true},
+                {"data_prefix"          , data_prefix},
                 {"txs"                  , mstch::array{}}
         };
 
@@ -1787,12 +1790,18 @@ public:
 
             const size_t magiclen = strlen(SIGNED_TX_PREFIX);
 
+            string data_prefix = xmreg::make_printable(decoded_raw_tx_data.substr(0, magiclen));
+
             if (strncmp(decoded_raw_tx_data.c_str(), SIGNED_TX_PREFIX, magiclen) != 0)
             {
-                cout << "The data is neither unsigned nor signed tx!" << endl;
-                return string( "The data is neither unsigned nor signed tx!");
+                string msg = fmt::format("The data is neither unsigned nor signed tx! Its prefix is: {:s}",
+                                         data_prefix);
+
+                cout << msg << endl;
+                return string(msg);
             }
 
+            context["data_prefix"] = data_prefix;
 
             bool r {false};
 
@@ -2055,12 +2064,15 @@ public:
 
         const size_t magiclen = strlen(SIGNED_TX_PREFIX);
 
+        string data_prefix = xmreg::make_printable(decoded_raw_tx_data.substr(0, magiclen));
+
         // initalize page template context map
         mstch::map context {
                 {"testnet"              , testnet},
                 {"have_raw_tx"          , true},
                 {"has_error"            , false},
                 {"error_msg"            , string {}},
+                {"data_prefix"          , data_prefix},
                 {"txs"                  , mstch::array{}}
         };
 
@@ -2074,7 +2086,8 @@ public:
 
         if (strncmp(decoded_raw_tx_data.c_str(), SIGNED_TX_PREFIX, magiclen) != 0)
         {
-            string error_msg = fmt::format("The data does not appear to be signed raw tx!");
+            string error_msg = fmt::format("The data does not appear to be signed raw tx! Data prefix: {:s}",
+                                           data_prefix);
 
             context["has_error"] = true;
             context["error_msg"] = error_msg;
diff --git a/src/templates/checkrawtx.html b/src/templates/checkrawtx.html
index 4e987f4..c532fba 100644
--- a/src/templates/checkrawtx.html
+++ b/src/templates/checkrawtx.html
@@ -22,6 +22,9 @@
     </div>
 
     <div class="center">
+
+        <h3>Data file prefix: {{data_prefix}}</h3>
+
         {{#unsigned_tx_given}}
             <h3>Details of unsigned raw tx data given</h3>
 
diff --git a/src/tools.cpp b/src/tools.cpp
index e4357da..078541f 100644
--- a/src/tools.cpp
+++ b/src/tools.cpp
@@ -1245,5 +1245,43 @@ make_tx_from_json(const string& json_str, transaction& tx)
     return true;
 }
 
+
+string
+make_printable(const string& in_s)
+{
+    string output;
+
+    for (char c: in_s)
+    {
+
+        if (isprint(c))
+        {
+            output += c;
+        }
+        else
+        {
+            switch(c){
+                case '\000': output += "\\000";break;
+                case '\001': output += "\\001";break;
+                case '\002': output += "\\002";break;
+                case '\003': output += "\\003";break;
+                case '\004': output += "\\004";break;
+                case '\005': output += "\\005";break;
+                case '\006': output += "\\006";break;
+                case '\007': output += "\\007";break;
+                // there are more case but for now its ok
+                default:
+                    stringstream ss;
+                    ss << std::hex << (int)c;
+                    output += "0x" + ss.str();
+                    break;
+            }
+        }
+
+    }
+
+    return output;
+}
+
 }
 
diff --git a/src/tools.h b/src/tools.h
index e81a0d6..e165e64 100644
--- a/src/tools.h
+++ b/src/tools.h
@@ -297,6 +297,8 @@ void chunks(Iterator begin,
 bool
 make_tx_from_json(const string& json_str, transaction& tx);
 
+string
+make_printable(const string& in_s);
 }
 
 #endif //XMREG01_TOOLS_H