--- cups-1.3.9/filter/rastertohp.c	2008-07-11 15:48:49.000000000 -0700
+++ rastertohp.c	2009-03-15 09:43:31.168180054 -0700
@@ -244,9 +244,12 @@
 
     if (!ppd || ppd->model_number != 2)
     {
-      if (header->Duplex)
+      if (header->Duplex) {
 	printf("\033&l%dS",			/* Set duplex mode */
                header->Duplex + header->Tumble);
+      } else {
+	printf("\033&l0S");			/* Turn off duplex mode */
+      }
 
       printf("\033&l0L");			/* Turn off perforation skip */
     }