diff --git a/core/product_config.mk b/core/product_config.mk
index 3237801..0a693f4 100644
--- a/core/product_config.mk
+++ b/core/product_config.mk
@@ -193,6 +193,12 @@
   extra_locales :=
 endif
 
+# Default to medium-density assets.
+# (Can be overridden in the device config, e.g.: PRODUCT_LOCALES += hdpi)
+PRODUCT_LOCALES := $(strip \
+	$(PRODUCT_LOCALES) \
+	$(if $(filter %dpi,$(PRODUCT_LOCALES)),,mdpi))
+
 # Assemble the list of options.
 PRODUCT_AAPT_CONFIG := $(PRODUCT_LOCALES)