+compile: linux-compile image_compile
+install: image_clean linux-install sdk_install image_install imagebuilder_install
+clean: linux-clean sdk-clean imagebuilder-clean image_clean
+
+prereq: FORCE
+ $(MAKE) -C linux/$(BOARD)-$(KERNEL) prereq
+ $(MAKE) -C $(IMAGE_DIR) prereq
+
+sdk_install: FORCE
+ $(MAKE) -C sdk install