diff --git a/Marlin/src/pins/stm32f1/pins_LONGER3D_LK.h b/Marlin/src/pins/stm32f1/pins_LONGER3D_LK.h
index 222698fa11..37ac753fc8 100644
--- a/Marlin/src/pins/stm32f1/pins_LONGER3D_LK.h
+++ b/Marlin/src/pins/stm32f1/pins_LONGER3D_LK.h
@@ -154,6 +154,13 @@
   #define LCD_BRIGHTNESS_DEFAULT TFT_BACKLIGHT_PWM
 #endif
 
+//
+// SD Support
+//
+#ifndef SDCARD_CONNECTION
+  #define SDCARD_CONNECTION              ONBOARD
+#endif
+
 #if SD_CONNECTION_IS(ONBOARD)
   #define ONBOARD_SDIO
   #define SD_SS_PIN                         -1    // else SDSS set to PA4 in M43 (spi_pins.h)