Applying suggestions by @thinkyhead at MarlinFirmware/Marlin#3049.

 - Remove the forced activation of SDSUPPORT, I guess people may use the ZUM
3D board and not the LCD module.
 - Fixed the tab issue within boards.h file.

Marlin/Conditionals.h

@@ -51,7 +51,6 @@
 
   #if ENABLED(BQ_LCD_SMART_CONTROLLER)
     #define REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER
-    #define SDSUPPORT
 
     #ifndef ENCODER_PULSES_PER_STEP
       #define ENCODER_PULSES_PER_STEP 4

Marlin/boards.h

@@ -61,7 +61,7 @@
 #define BOARD_MKS_BASE          40   // MKS BASE 1.0
 #define BOARD_BAM_DICE          401  // 2PrintBeta BAM&DICE with STK drivers
 #define BOARD_BAM_DICE_DUE      402  // 2PrintBeta BAM&DICE Due with STK drivers
-#define BOARD_BQ_ZUM_MEGA_3D	503  // bq ZUM Mega 3D
+#define BOARD_BQ_ZUM_MEGA_3D    503  // bq ZUM Mega 3D
 
 #define BOARD_99                99   // This is in pins.h but...?
 

Marlin/example_configurations/Hephestos_2/Configuration.h

@@ -666,7 +666,7 @@ const bool Z_MIN_PROBE_ENDSTOP_INVERTING = false; // set to true to invert the l
 
 //#define ULTRA_LCD  //general LCD support, also 16x2
 //#define DOGLCD  // Support for SPI LCD 128x64 (Controller ST7565R graphic Display Family)
-//#define SDSUPPORT // Enable SD Card Support in Hardware Console
+#define SDSUPPORT // Enable SD Card Support in Hardware Console
 // Changed behaviour! If you need SDSUPPORT uncomment it!
 //#define SDSLOW // Use slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
 //#define SDEXTRASLOW // Use even slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)