diff --git a/build/tasks/kernel.mk b/build/tasks/kernel.mk
index 32af3c9..19663c7 100644
--- a/build/tasks/kernel.mk
+++ b/build/tasks/kernel.mk
@@ -346,6 +346,7 @@
 ifeq ($(BOARD_KERNEL_SEPARATED_DTBO),true)
 $(BOARD_PREBUILT_DTBOIMAGE):
 	@echo "Building dtbo.img"
+	rm -rf $(DTBO_OUT)
 	$(call make-dtbo-target,$(KERNEL_DEFCONFIG))
 	$(call make-dtbo-target,dtbs)
 ifdef BOARD_DTBO_CFG
@@ -366,6 +367,7 @@
 ifeq ($(BOARD_PREBUILT_DTBIMAGE_DIR),)
 $(INSTALLED_DTBIMAGE_TARGET): $(DTC)
 	@echo "Building dtb.img"
+	rm -rf $(DTB_OUT)
 	$(call make-dtb-target,$(KERNEL_DEFCONFIG))
 	$(call make-dtb-target,dtbs)
 	cat $(shell find $(DTB_OUT)/arch/$(KERNEL_ARCH)/boot/dts -type f -name "*.dtb" | sort) > $@