diff --git a/hostsidetests/appsecurity/test-apps/PrivilegedUpdateApp/Android.mk b/hostsidetests/appsecurity/test-apps/PrivilegedUpdateApp/Android.mk
index e86fae9..17a1716 100644
--- a/hostsidetests/appsecurity/test-apps/PrivilegedUpdateApp/Android.mk
+++ b/hostsidetests/appsecurity/test-apps/PrivilegedUpdateApp/Android.mk
@@ -48,9 +48,10 @@
 LOCAL_CERTIFICATE := PRESIGNED
 LOCAL_COMPATIBILITY_SUITE := cts vts general-tests
 
-my_archs := arm x86
-my_src_arch := $(call get-prebuilt-src-arch, $(my_archs))
-LOCAL_REPLACE_PREBUILT_APK_INSTALLED := $(LOCAL_PATH)/apk/$(my_src_arch)/CtsShimPrivUpgrade.apk
+# The 'arm' apk has both arm and arm64 so's. Same for x86/x86_64.
+my_apk_dir := $(subst arm64,arm,$(TARGET_ARCH))
+my_apk_dir := $(subst x86_64,x86,$(my_apk_dir))
+LOCAL_REPLACE_PREBUILT_APK_INSTALLED := $(LOCAL_PATH)/apk/$(my_apk_dir)/CtsShimPrivUpgrade.apk
 
 include $(BUILD_PREBUILT)
 
@@ -67,8 +68,8 @@
 LOCAL_CERTIFICATE := PRESIGNED
 LOCAL_COMPATIBILITY_SUITE := cts vts general-tests
 
-my_archs := arm x86
-my_src_arch := $(call get-prebuilt-src-arch, $(my_archs))
-LOCAL_REPLACE_PREBUILT_APK_INSTALLED := $(LOCAL_PATH)/apk/$(my_src_arch)/CtsShimPrivUpgradeWrongSHA.apk
+LOCAL_REPLACE_PREBUILT_APK_INSTALLED := $(LOCAL_PATH)/apk/$(my_apk_dir)/CtsShimPrivUpgradeWrongSHA.apk
 
 include $(BUILD_PREBUILT)
+
+my_apk_dir :=