From efeb6efe773ed137f3a1d225f98b0f0b929c320b Mon Sep 17 00:00:00 2001
From: Luu Lac <45380455+shitcreek@users.noreply.github.com>
Date: Thu, 24 Oct 2019 12:04:45 -0500
Subject: [PATCH] Set pullup on BTN_BACK pin (#15654)

---
 Marlin/src/lcd/ultralcd.cpp  | 4 ++++
 Marlin/src/libs/vector_3.cpp | 6 +++---
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/Marlin/src/lcd/ultralcd.cpp b/Marlin/src/lcd/ultralcd.cpp
index e67a7812f..54d13c29c 100644
--- a/Marlin/src/lcd/ultralcd.cpp
+++ b/Marlin/src/lcd/ultralcd.cpp
@@ -295,6 +295,10 @@ void MarlinUI::init() {
       SET_INPUT_PULLUP(BTN_ENC);
     #endif
 
+    #if BUTTON_EXISTS(BACK)
+      SET_INPUT_PULLUP(BTN_BACK);
+    #endif
+
     #if BUTTON_EXISTS(UP)
       SET_INPUT(BTN_UP);
     #endif
diff --git a/Marlin/src/libs/vector_3.cpp b/Marlin/src/libs/vector_3.cpp
index 41ea3ec97..f50fde5ed 100644
--- a/Marlin/src/libs/vector_3.cpp
+++ b/Marlin/src/libs/vector_3.cpp
@@ -71,9 +71,9 @@ void vector_3::normalize() {
 // Apply a rotation to the matrix
 void vector_3::apply_rotation(const matrix_3x3 &matrix) {
   const float _x = x, _y = y, _z = z;
-  x = _x * matrix.vectors[0][0] + _y * matrix.vectors[1][0] + _z * matrix.vectors[2][0];
-  y = _x * matrix.vectors[0][1] + _y * matrix.vectors[1][1] + _z * matrix.vectors[2][1];
-  z = _x * matrix.vectors[0][2] + _y * matrix.vectors[1][2] + _z * matrix.vectors[2][2];
+  *this = { matrix.vectors[0][0] * _x + matrix.vectors[1][0] * _y + matrix.vectors[2][0] * _z,
+            matrix.vectors[0][1] * _x + matrix.vectors[1][1] * _y + matrix.vectors[2][1] * _z,
+            matrix.vectors[0][2] * _x + matrix.vectors[1][2] * _y + matrix.vectors[2][2] * _z };
 }
 
 void vector_3::debug(PGM_P const title) {