diff --git a/sdk/xtdk/bltypes.h b/sdk/xtdk/bltypes.h
index 8f75f5a..20c33d2 100644
--- a/sdk/xtdk/bltypes.h
+++ b/sdk/xtdk/bltypes.h
@@ -12,11 +12,16 @@
 #include <xttypes.h>
 
 
+/* Debug port type definitions */
+#define XTBL_DEBUGPORT_SCREEN                                       1
+#define XTBL_DEBUGPORT_SERIAL                                       2
+
 /* XTLDR configuration data */
 typedef struct _XTBM_CONFIGURATION
 {
     PWCHAR Default;
     PWCHAR Debug;
+    ULONG DebugPort;
     BOOLEAN Shell;
     PWCHAR Theme;
     ULONG Timeout;