diff --git a/pidrive/sirom.s b/pidrive/sirom.s
index b4fc4f3..4259b66 100755
--- a/pidrive/sirom.s
+++ b/pidrive/sirom.s
@@ -4,7 +4,7 @@
 ;*
 ;****************************************
 
-.DEFINE	SIG	"SI"
+.DEFINE	SIG	"SD"
 
 	.INCLUDE "romincs.s"