diff --git a/Makefile b/Makefile
index b131054..69358c3 100644
--- a/Makefile
+++ b/Makefile
@@ -49,15 +49,11 @@
 ## Common options
 ##
 VERBOSE ?= 0
-CUSTOM_KERNEL_IMAGE = 0
 ARCH = arm64
 
+DEFAULT_KERNEL_IMAGE := $(LINUX_OUT)/arch/arm64/boot/Image
 # KERNEL_IMAGE can be set to use own custom kernel image.
-ifdef KERNEL_IMAGE
-CUSTOM_KERNEL_IMAGE = 1
-else
-KERNEL_IMAGE := $(LINUX_OUT)/arch/arm64/boot/Image
-endif
+KERNEL_IMAGE ?= $(DEFAULT_KERNEL_IMAGE)
 
 ##
 ## Toolchain options and variables
@@ -252,15 +248,10 @@
 	$(call copy_to_dist, $(LINUX_DIST_FILES), $(LINUX_DIST))
 
 .PHONY: linux_image
-linux_image: $(LINUX_CONFIG)
+linux_image $(DEFAULT_KERNEL_IMAGE): $(LINUX_CONFIG)
 	+ $(LINUX_MAKE) Image.gz
 	$(call copy_to_dist, $(LINUX_DIST_FILES), $(LINUX_DIST))
 
-# If using own kernel image (KERNEL_IMAGE is set in the environment), then skip.
-ifeq ($(CUSTOM_KERNEL_IMAGE), 0)
-$(KERNEL_IMAGE): linux_image
-endif
-
 .PHONY: linux_clean
 linux_clean:
 	+ $(LINUX_MAKE) mrproper