From 4793c34c5365e7720c0a53c7bd88188aaf37f227 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <github@thinkyhead.com>
Date: Tue, 28 Nov 2017 17:21:33 -0600
Subject: [PATCH] Fix M290 boolval bug

Fix #8577
---
 Marlin/src/gcode/motion/M290.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Marlin/src/gcode/motion/M290.cpp b/Marlin/src/gcode/motion/M290.cpp
index 2b62f5d569..00426ad231 100644
--- a/Marlin/src/gcode/motion/M290.cpp
+++ b/Marlin/src/gcode/motion/M290.cpp
@@ -52,7 +52,7 @@ void GcodeSuite::M290() {
         const float offs = constrain(parser.value_axis_units((AxisEnum)a), -2, 2);
         thermalManager.babystep_axis((AxisEnum)a, offs * planner.axis_steps_per_mm[a]);
         #if ENABLED(BABYSTEP_ZPROBE_OFFSET)
-          if (a == Z_AXIS && parser.boolval('P', true)) mod_zprobe_zoffset(offs);
+          if (a == Z_AXIS && (!parser.seen('P') || parser.value_bool())) mod_zprobe_zoffset(offs);
         #endif
       }
   #else
@@ -60,7 +60,7 @@ void GcodeSuite::M290() {
       const float offs = constrain(parser.value_axis_units(Z_AXIS), -2, 2);
       thermalManager.babystep_axis(Z_AXIS, offs * planner.axis_steps_per_mm[Z_AXIS]);
       #if ENABLED(BABYSTEP_ZPROBE_OFFSET)
-        if (parser.boolval('P', true)) mod_zprobe_zoffset(offs);
+        if (!parser.seen('P') || parser.value_bool()) mod_zprobe_zoffset(offs);
       #endif
     }
   #endif