From 92ed9a2bb6d90a969f2ceaf0a73ebe3c0cdc4c16 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <github@thinkyhead.com>
Date: Mon, 15 Apr 2019 23:46:36 -0500
Subject: [PATCH] Fix is_M29

Followup for #13013
---
 Marlin/src/gcode/queue.cpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Marlin/src/gcode/queue.cpp b/Marlin/src/gcode/queue.cpp
index f448efb117..817d6bca18 100644
--- a/Marlin/src/gcode/queue.cpp
+++ b/Marlin/src/gcode/queue.cpp
@@ -526,8 +526,9 @@ void gcode_line_error(PGM_P const err, const int8_t port) {
 
 #endif // BINARY_FILE_TRANSFER
 
-FORCE_INLINE bool is_M29(const char * const cmd) {
-  return cmd[0] == 'M' && cmd[1] == '2' && cmd[2] == '9' && !WITHIN(cmd[3], '0', '9');
+FORCE_INLINE bool is_M29(const char * const cmd) {  // matches "M29" & "M29 ", but not "M290", etc
+  const char * const m29 = strstr_P(cmd, PSTR("M29"));
+  return m29 && !NUMERIC(m29[3]);
 }
 
 /**