diff --git a/Marlin/ultralcd.cpp b/Marlin/ultralcd.cpp
index 9d6dd3e455..990d79ec89 100755
--- a/Marlin/ultralcd.cpp
+++ b/Marlin/ultralcd.cpp
@@ -3154,6 +3154,8 @@ void lcd_reset_alert_level() { lcd_status_message_level = 0; }
 
   #if (ENABLED(LCD_I2C_TYPE_MCP23017) || ENABLED(LCD_I2C_TYPE_MCP23008)) && ENABLED(DETECT_DEVICE)
     bool lcd_detected() { return lcd.LcdDetected() == 1; }
+  #else
+    bool lcd_detected() { return true; }
   #endif
 
 #endif // ULTIPANEL
diff --git a/Marlin/ultralcd.h b/Marlin/ultralcd.h
index f0d0a42844..8e2227af4e 100644
--- a/Marlin/ultralcd.h
+++ b/Marlin/ultralcd.h
@@ -43,12 +43,7 @@
   void lcd_reset_alert_level();
   void lcd_kill_screen();
   void kill_screen(const char* lcd_msg);
-
-  #if (ENABLED(LCD_I2C_TYPE_MCP23017) || ENABLED(LCD_I2C_TYPE_MCP23008)) && ENABLED(DETECT_DEVICE)
-    bool lcd_detected();
-  #else
-    inline bool lcd_detected() { return true; }
-  #endif
+  bool lcd_detected(void);
 
   #if HAS_BUZZER
     void lcd_buzz(long duration, uint16_t freq);