diff --git a/core/Makefile b/core/Makefile
index 8cc7229..154ed53 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -863,7 +863,7 @@
 # -----------------------------------------------------------------
 # Cert-to-package mapping.  Used by the post-build signing tools.
 # Use a macro to add newline to each echo command
-# $1 package name
+# $1 stem name of the package
 # $2 certificate
 # $3 private key
 # $4 compressed
@@ -893,8 +893,8 @@
 	@rm -f $@
 	$(foreach p,$(sort $(PACKAGES)),\
 	  $(if $(PACKAGES.$(p).EXTERNAL_KEY),\
-	    $(call _apkcerts_write_line,$(p),"EXTERNAL","",$(PACKAGES.$(p).COMPRESSED),$(PACKAGES.$(p).PARTITION),$@),\
-	    $(call _apkcerts_write_line,$(p),$(PACKAGES.$(p).CERTIFICATE),$(PACKAGES.$(p).PRIVATE_KEY),$(PACKAGES.$(p).COMPRESSED),$(PACKAGES.$(p).PARTITION),$@)))
+	    $(call _apkcerts_write_line,$(PACKAGES.$(p).STEM),"EXTERNAL","",$(PACKAGES.$(p).COMPRESSED),$(PACKAGES.$(p).PARTITION),$@),\
+	    $(call _apkcerts_write_line,$(PACKAGES.$(p).STEM),$(PACKAGES.$(p).CERTIFICATE),$(PACKAGES.$(p).PRIVATE_KEY),$(PACKAGES.$(p).COMPRESSED),$(PACKAGES.$(p).PARTITION),$@)))
 	# In case value of PACKAGES is empty.
 	$(hide) touch $@
 
diff --git a/core/soong_app_prebuilt.mk b/core/soong_app_prebuilt.mk
index 6dc396c..a3de688 100644
--- a/core/soong_app_prebuilt.mk
+++ b/core/soong_app_prebuilt.mk
@@ -157,6 +157,12 @@
 include $(BUILD_SYSTEM)/app_certificate_validate.mk
 PACKAGES.$(LOCAL_MODULE).OVERRIDES := $(strip $(LOCAL_OVERRIDES_PACKAGES))
 
+ifneq ($(LOCAL_MODULE_STEM),)
+  PACKAGES.$(LOCAL_MODULE).STEM := $(LOCAL_MODULE_STEM)
+else
+  PACKAGES.$(LOCAL_MODULE).STEM := $(LOCAL_MODULE)
+endif
+
 # Set a actual_partition_tag (calculated in base_rules.mk) for the package.
 PACKAGES.$(LOCAL_MODULE).PARTITION := $(actual_partition_tag)