Support for Extrudrboard in Printrboard Rev.F

Marlin/src/Marlin.cpp

@@ -661,7 +661,7 @@ void setup() {
     Max7219_init();
   #endif
 
-  #ifdef DISABLE_JTAG
+  #if ENABLED(DISABLE_JTAG)
     // Disable JTAG on AT90USB chips to free up pins for IO
     MCUCR = 0x80;
     MCUCR = 0x80;