diff --git a/Marlin/src/gcode/parser.h b/Marlin/src/gcode/parser.h
index 5c942b70b..e35585670 100644
--- a/Marlin/src/gcode/parser.h
+++ b/Marlin/src/gcode/parser.h
@@ -145,7 +145,7 @@ public:
     // Code is found in the string. If not found, value_ptr is unchanged.
     // This allows "if (seen('A')||seen('B'))" to use the last-found value.
     static bool seen(const char c) {
-      const char *p = strchr(command_args, c);
+      char *p = strchr(command_args, c);
       const bool b = !!p;
       if (b) value_ptr = valid_float(&p[1]) ? &p[1] : (char*)NULL;
       return b;