diff --git a/firmware/isp.c b/firmware/isp.c
index 5e51bf0..ab75b6e 100755
--- a/firmware/isp.c
+++ b/firmware/isp.c
@@ -126,7 +126,7 @@ void ispConnect() {
 	}
 	
 	/* Initial extended address value */
-	isp_hiaddr = 0;
+	isp_hiaddr = 0xFF;
 }
 
 void ispDisconnect() {