Boot screen no longer shown when activating menu.

- On Hibiscus, will allow SD card to be inserted/removed without garbled screen
- On other FW, will eliminate boot screen flash when entering menu.

Marlin/Conditionals_LulzBot.h

@@ -211,6 +211,11 @@
 //      Back port of upstream https://github.com/MarlinFirmware/Marlin/commit/6ed284061580ffc6eef40df391afb30d2f8b45f5
 #define LULZBOT_OCTOPRINT_RX_BUFFER_OVERFLOW_WORKAROUND delay(2);
 
+/* In Marlin, the custom boot screen is incorrectly being drawn during
+ * lcd_implementation_init, this causes the boot screen to flash
+ * before entering menus, and also screws up the new modern UI */
+#define LULZBOT_CUSTOM_BOOTSCREEN_DURING_INIT_WORKAROUND
+
 /************************* EXPERIMENTAL FEATURES ******************************/
 
 #if defined(LULZBOT_USE_EXPERIMENTAL_FEATURES)

Marlin/ultralcd.cpp

@@ -4363,6 +4363,14 @@ void lcd_init() {
     #endif
   );
 
+  #if ENABLED(SHOW_BOOTSCREEN) && defined(LULZBOT_CUSTOM_BOOTSCREEN_DURING_INIT_WORKAROUND)
+    #if ENABLED(SHOW_CUSTOM_BOOTSCREEN)
+      lcd_custom_bootscreen();
+    #else
+      lcd_bootscreen();
+    #endif
+  #endif
+
   #if ENABLED(NEWPANEL)
     #if BUTTON_EXISTS(EN1)
       SET_INPUT_PULLUP(BTN_EN1);

Marlin/ultralcd_impl_DOGM.h

@@ -339,7 +339,7 @@ static void lcd_implementation_init() {
     u8g.setRot270();  // Rotate screen by 270°
   #endif
 
-  #if ENABLED(SHOW_BOOTSCREEN)
+  #if ENABLED(SHOW_BOOTSCREEN) && not defined(LULZBOT_CUSTOM_BOOTSCREEN_DURING_INIT_WORKAROUND)
     #if ENABLED(SHOW_CUSTOM_BOOTSCREEN)
       lcd_custom_bootscreen();
     #else

Marlin/ultralcd_lulzbot.h

@@ -652,7 +652,6 @@ const  uint8_t crc =
     }
     draw_progress_bar(percent_done);
 
-
     // Update the fan and bed animations
     if(fan_speed > 0) {
       draw_fan_icon(blink);