diff --git a/core/main.mk b/core/main.mk
index c1059d7..eccae2d 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -889,47 +889,40 @@
 # $(2): The initial module name list.
 # Returns empty string (maybe with some whitespaces).
 define expand-required-modules
-$(eval _erm_new_modules := $(sort $(filter-out $($(1)),\
-  $(foreach m,$(2),$(ALL_MODULES.$(m).REQUIRED)))))\
+$(eval _erm_req := $(foreach m,$(2),$(ALL_MODULES.$(m).REQUIRED))) \
+$(eval _erm_new_modules := $(sort $(filter-out $($(1)),$(_erm_req))))\
 $(if $(_erm_new_modules),$(eval $(1) += $(_erm_new_modules))\
   $(call expand-required-modules,$(1),$(_erm_new_modules)))
 endef
 
+# Determines the files a particular product installs.
+# The base list of modules to build for this product is specified
+# by the appropriate product definition file, which was included
+# by product_config.mk.
+# $(1): product makefile
+define product-installed-files
+  $(eval _pif_modules := $(PRODUCTS.$(strip $(1)).PRODUCT_PACKAGES)) \
+  $(if $(BOARD_VNDK_VERSION),$(eval _pif_modules += vndk_package)) \
+  $(eval ### Filter out the overridden packages and executables before doing expansion) \
+  $(eval _pif_overrides := $(foreach p, $(_pif_modules), $(PACKAGES.$(p).OVERRIDES))) \
+  $(eval _pif_overrides += $(foreach m, $(_pif_modules), $(EXECUTABLES.$(m).OVERRIDES))) \
+  $(eval _pif_modules := $(filter-out $(_pif_overrides), $(_pif_modules))) \
+  $(eval ### Resolve the :32 :64 module name) \
+  $(eval _pif_modules_32 := $(patsubst %:32,%,$(filter %:32, $(_pif_modules)))) \
+  $(eval _pif_modules_64 := $(patsubst %:64,%,$(filter %:64, $(_pif_modules)))) \
+  $(eval _pif_modules_rest := $(filter-out %:32 %:64,$(_pif_modules))) \
+  $(eval ### Note for 32-bit product, 32 and 64 will be added as their original module names.) \
+  $(eval _pif_modules := $(call get-32-bit-modules-if-we-can, $(_pif_modules_32))) \
+  $(eval _pif_modules += $(_pif_modules_64)) \
+  $(eval ### For the rest we add both) \
+  $(eval _pif_modules += $(call get-32-bit-modules, $(_pif_modules_rest))) \
+  $(eval _pif_modules += $(_pif_modules_rest)) \
+  $(call expand-required-modules,_pif_modules,$(_pif_modules)) \
+  $(call module-installed-files, $(_pif_modules))
+endef
+
 ifdef FULL_BUILD
-  # The base list of modules to build for this product is specified
-  # by the appropriate product definition file, which was included
-  # by product_config.mk.
-  product_MODULES := $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_PACKAGES)
-ifdef BOARD_VNDK_VERSION
-  product_MODULES += vndk_package
-endif
-  # Filter out the overridden packages before doing expansion
-  product_MODULES := $(filter-out $(foreach p, $(product_MODULES), \
-      $(PACKAGES.$(p).OVERRIDES)), $(product_MODULES))
-  # Filter out executables as well
-  product_MODULES := $(filter-out $(foreach m, $(product_MODULES), \
-      $(EXECUTABLES.$(m).OVERRIDES)), $(product_MODULES))
-
-  # Resolve the :32 :64 module name
-  modules_32 := $(patsubst %:32,%,$(filter %:32, $(product_MODULES)))
-  modules_64 := $(patsubst %:64,%,$(filter %:64, $(product_MODULES)))
-  modules_rest := $(filter-out %:32 %:64,$(product_MODULES))
-  # Note for 32-bit product, $(modules_32) and $(modules_64) will be
-  # added as their original module names.
-  product_MODULES := $(call get-32-bit-modules-if-we-can, $(modules_32))
-  product_MODULES += $(modules_64)
-  # For the rest we add both
-  product_MODULES += $(call get-32-bit-modules, $(modules_rest))
-  product_MODULES += $(modules_rest)
-
-  $(call expand-required-modules,product_MODULES,$(product_MODULES))
-
-  product_FILES := $(call module-installed-files, $(product_MODULES))
-  ifeq (0,1)
-    $(info product_FILES for $(TARGET_DEVICE) ($(INTERNAL_PRODUCT)):)
-    $(foreach p,$(product_FILES),$(info :   $(p)))
-    $(error done)
-  endif
+  product_FILES := $(call product-installed-files, $(INTERNAL_PRODUCT))
 else
   # We're not doing a full build, and are probably only including
   # a subset of the module makefiles.  Don't try to build any modules
@@ -938,6 +931,12 @@
   product_FILES :=
 endif
 
+ifeq (0,1)
+  $(info product_FILES for $(TARGET_DEVICE) ($(INTERNAL_PRODUCT)):)
+  $(foreach p,$(product_FILES),$(info :   $(p)))
+  $(error done)
+endif
+
 eng_MODULES := $(sort \
         $(call get-tagged-modules,eng) \
         $(call module-installed-files, $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_PACKAGES_ENG)) \