diff --git a/CommandStation-EX.ino b/CommandStation-EX.ino
index ba00b25..61b23ec 100644
--- a/CommandStation-EX.ino
+++ b/CommandStation-EX.ino
@@ -168,7 +168,7 @@ void loop()
     DCCPacket p = dccSniffer->fetchPacket();
     if (p.len() != 0) {
       if (DCCDecoder::parse(p)) {
-	p.print(Serial);
+	p.print();
       }
     }
   }
diff --git a/DCCDecoder.cpp b/DCCDecoder.cpp
index 1304367..6e7d858 100644
--- a/DCCDecoder.cpp
+++ b/DCCDecoder.cpp
@@ -42,7 +42,8 @@ bool DCCDecoder::parse(DCCPacket &p) {
   for (byte n = 0; n < p.len(); n++)
     checksum ^= d[n];
   if (checksum) {  // Result should be zero, if not it's an error!
-    DIAG(F("Checksum error"));
+    DIAG(F("Checksum error:"));
+    p.print();
     return false;
   }
 
diff --git a/DCCPacket.h b/DCCPacket.h
index e754142..8258378 100644
--- a/DCCPacket.h
+++ b/DCCPacket.h
@@ -20,6 +20,7 @@
 #ifndef DCCPacket_h
 #define DCCPacket_h
 #include <strings.h>
+#include "defines.h"
 
 class DCCPacket {
 public:
@@ -63,13 +64,15 @@ public:
       return true;
     return (bcmp(_data, right._data, _len) == 0);
   };
-  void print(HardwareSerial &s) {
-    s.print("<* DCCPACKET ");
+  void print() {
+    static const char hexchars[]="0123456789ABCDEF";
+    USB_SERIAL.print(F("<* DCCPACKET "));
     for (byte n = 0; n< _len; n++) {
-      s.print(_data[n], HEX);
-      s.print(" ");
+      USB_SERIAL.print(hexchars[_data[n]>>4]);
+      USB_SERIAL.print(hexchars[_data[n] & 0x0f]);
+      USB_SERIAL.print(' ');
     }
-    s.print("*>\n");
+    USB_SERIAL.print(F("*>\n"));
   };
   inline byte len() {return _len;};
   inline byte *data() {return _data;};