diff --git a/src/nwipe.c b/src/nwipe.c
index 4c4f40f..d1ef632 100644
--- a/src/nwipe.c
+++ b/src/nwipe.c
@@ -812,7 +812,7 @@ int cleanup()
 }
 void check_for_autopoweroff( void )
 {
-    char cmd[] = "shutdown -P +1 \"System going down in one minute\"";
+    char cmd[] = "shutdown -Ph +1 \"System going down in one minute\"";
     FILE* fp;
     int r;  // A result buffer.