diff --git a/pigpio.py b/pigpio.py
index 7e411e7..a1b3544 100644
--- a/pigpio.py
+++ b/pigpio.py
@@ -3418,7 +3418,7 @@ class pi():
       status = pi.bb_serial_invert(17, 1)
       ...
       """
-      return _u2i(_pigpio_command(self.sl, _PI_CMD_SLRI, user_gpio, invert, 0))
+      return _u2i(_pigpio_command(self.sl, _PI_CMD_SLRI, user_gpio, invert))
 
    def custom_1(self, arg1=0, arg2=0, argx=[]):
       """
diff --git a/x_pigs b/x_pigs
index 1f4f36b..923734a 100755
--- a/x_pigs
+++ b/x_pigs
@@ -49,7 +49,7 @@ s=$(pigs bs2 0)
 if [[ $s = "" ]]; then echo "BS2 ok"; else echo "BS2 fail ($s)"; fi
 
 s=$(pigs h)
-if [[ ${#s} = 4263 ]]; then echo "HELP ok"; else echo "HELP fail (${#s})"; fi
+if [[ ${#s} = 4321 ]]; then echo "HELP ok"; else echo "HELP fail (${#s})"; fi
 
 s=$(pigs hwver)
 if [[ $s -ne 0 ]]; then echo "HWVER ok"; else echo "HWVER fail ($s)"; fi