Slightly more prominent LUFA Mass-storage bootloader warning. (#13163)

bootloader.mk

@@ -92,10 +92,14 @@ ifeq ($(strip $(BOOTLOADER)), lufa-ms)
     OPT_DEFS += -DBOOTLOADER_MS
     BOOTLOADER_SIZE = 6144
     FIRMWARE_FORMAT = bin
-    $(info LUFA MASS STORAGE Bootloader selected)
-    $(info DO NOT USE THIS BOOTLOADER IN NEW PROJECTS!)
-    $(info It is extremely prone to bricking, and is only included to support existing boards.)
-    $(info )
+cpfirmware: lufa_warning
+.INTERMEDIATE: lufa_warning
+lufa_warning: $(FIRMWARE_FORMAT)
+	$(info @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@)
+	$(info LUFA MASS STORAGE Bootloader selected)
+	$(info DO NOT USE THIS BOOTLOADER IN NEW PROJECTS!)
+	$(info It is extremely prone to bricking, and is only included to support existing boards.)
+	$(info @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@)
 endif
 ifdef BOOTLOADER_SIZE
     OPT_DEFS += -DBOOTLOADER_SIZE=$(strip $(BOOTLOADER_SIZE))