Don't enable lcd update inside mmu_eject_filament().

Firmware/lcd.h

@@ -150,6 +150,29 @@ extern void lcd_update_enable(uint8_t enabled);
 
 extern void lcd_buttons_update(void);
 
+//! @brief Helper class to temporarily disable LCD updates
+//!
+//! When constructed (on stack), original state state of lcd_update_enabled is stored
+//! and LCD updates are disabled.
+//! When destroyed (gone out of scope), original state of LCD update is restored.
+//! It has zero overhead compared to storing bool saved = lcd_update_enabled
+//! and calling lcd_update_enable(false) and lcd_update_enable(saved).
+class LcdUpdateDisabler
+{
+public:
+    LcdUpdateDisabler(): m_updateEnabled(lcd_update_enabled)
+    {
+        lcd_update_enable(false);
+    }
+    ~LcdUpdateDisabler()
+    {
+        lcd_update_enable(m_updateEnabled);
+    }
+
+private:
+    bool m_updateEnabled;
+};
+
 
 
 

Firmware/mmu.cpp

@@ -1012,14 +1012,15 @@ void mmu_eject_filament(uint8_t filament, bool recover)
 		if (degHotend0() > EXTRUDE_MINTEMP)
 		{
 			st_synchronize();
-			lcd_update_enable(false);
-			lcd_clear();
-			lcd_set_cursor(0, 1); lcd_puts_P(_i("Ejecting filament"));
-			current_position[E_AXIS] -= 80;
-			plan_buffer_line(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS], 2500 / 60, active_extruder);
-			st_synchronize();
 
-			lcd_update_enable(true);
+			{
+			    LcdUpdateDisabler disableLcdUpdate;
+                lcd_clear();
+                lcd_set_cursor(0, 1); lcd_puts_P(_i("Ejecting filament"));
+                current_position[E_AXIS] -= 80;
+                plan_buffer_line(current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS], current_position[E_AXIS], 2500 / 60, active_extruder);
+                st_synchronize();
+			}
 
 			mmu_command(MMU_CMD_E0 + filament);
 			manage_response(false, false);