diff --git a/core/ninja.mk b/core/ninja.mk
index afdef7e..c31ae4e 100644
--- a/core/ninja.mk
+++ b/core/ninja.mk
@@ -1,8 +1,6 @@
 NINJA ?= prebuilts/ninja/$(HOST_PREBUILT_TAG)/ninja
 
-ifeq ($(USE_SOONG),true)
 include $(BUILD_SYSTEM)/soong.mk
-endif
 
 KATI_OUTPUT_PATTERNS := $(OUT_DIR)/build%.ninja $(OUT_DIR)/ninja%.sh
 
@@ -128,7 +126,7 @@
 ifeq ($(USE_SOONG),true)
 COMBINED_BUILD_NINJA := $(OUT_DIR)/combined$(KATI_NINJA_SUFFIX).ninja
 
-$(COMBINED_BUILD_NINJA): $(KATI_BUILD_NINJA) $(SOONG_ANDROID_MK)
+$(COMBINED_BUILD_NINJA): $(KATI_BUILD_NINJA)
 	$(hide) echo "builddir = $(OUT_DIR)" > $(COMBINED_BUILD_NINJA)
 	$(hide) echo "subninja $(SOONG_BUILD_NINJA)" >> $(COMBINED_BUILD_NINJA)
 	$(hide) echo "subninja $(KATI_BUILD_NINJA)" >> $(COMBINED_BUILD_NINJA)
@@ -148,7 +146,7 @@
 ifeq ($(KATI_EMULATE_FIND),false)
   KATI_FIND_EMULATOR :=
 endif
-$(KATI_BUILD_NINJA): $(CKATI) $(MAKEPARALLEL) $(SOONG_ANDROID_MK) FORCE
+$(KATI_BUILD_NINJA): $(CKATI) $(MAKEPARALLEL) run_soong FORCE
 	@echo Running kati to generate build$(KATI_NINJA_SUFFIX).ninja...
 	+$(hide) $(KATI_MAKEPARALLEL) $(CKATI) --ninja --ninja_dir=$(OUT_DIR) --ninja_suffix=$(KATI_NINJA_SUFFIX) --regen --ignore_dirty=$(OUT_DIR)/% --no_ignore_dirty=$(SOONG_ANDROID_MK) --ignore_optional_include=$(OUT_DIR)/%.P --detect_android_echo $(KATI_FIND_EMULATOR) -f build/core/main.mk $(KATI_GOALS) --gen_all_targets BUILDING_WITH_NINJA=true SOONG_ANDROID_MK=$(SOONG_ANDROID_MK)
 
diff --git a/core/soong.mk b/core/soong.mk
index e070d6b..e3ce46e 100644
--- a/core/soong.mk
+++ b/core/soong.mk
@@ -16,10 +16,15 @@
 
 SOONG := $(SOONG_OUT_DIR)/soong
 SOONG_BUILD_NINJA := $(SOONG_OUT_DIR)/build.ninja
-SOONG_ANDROID_MK := $(SOONG_OUT_DIR)/Android.mk
 SOONG_VARIABLES := $(SOONG_OUT_DIR)/soong.variables
 SOONG_IN_MAKE := $(SOONG_OUT_DIR)/.soong.in_make
 
+# Only include the Soong-generated Android.mk if we're merging the
+# Soong-defined binaries with Kati-defined binaries.
+ifeq ($(USE_SOONG),true)
+SOONG_ANDROID_MK := $(SOONG_OUT_DIR)/Android.mk
+endif
+
 # Bootstrap soong.  Run only the first time for clean builds
 $(SOONG):
 	$(hide) mkdir -p $(dir $@)
@@ -67,6 +72,8 @@
 	$(hide) mkdir -p $(dir $@)
 	$(hide) touch $@
 
-# Build an Android.mk listing all soong outputs as prebuilts
-$(SOONG_ANDROID_MK): $(SOONG) $(SOONG_VARIABLES) $(SOONG_IN_MAKE) FORCE
+# Run Soong, this implicitly create an Android.mk listing all soong outputs as
+# prebuilts.
+.PHONY: run_soong
+run_soong: $(SOONG) $(SOONG_VARIABLES) $(SOONG_IN_MAKE) FORCE
 	$(hide) $(SOONG) $(SOONG_BUILD_NINJA) $(NINJA_ARGS)