diff --git a/CleanSpec.mk b/CleanSpec.mk
index d5206bb..fc908de 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -320,6 +320,11 @@
 # an ABI change since the names will mangle differently.
 $(call add-clean-step, rm -rf $(OUT_DIR))
 
+# 5.1!
+$(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/build.prop)
+$(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/app/*)
+$(call add-clean-step, rm -rf $(PRODUCT_OUT)/obj/APPS/*)
+
 # ************************************************
 # NEWER CLEAN STEPS MUST BE AT THE END OF THE LIST
 # ************************************************
diff --git a/core/version_defaults.mk b/core/version_defaults.mk
index 1acc320..d87a032 100644
--- a/core/version_defaults.mk
+++ b/core/version_defaults.mk
@@ -41,7 +41,7 @@
   # which is the version that we reveal to the end user.
   # Update this value when the platform version changes (rather
   # than overriding it somewhere else).  Can be an arbitrary string.
-  PLATFORM_VERSION := LollipopMR1
+  PLATFORM_VERSION := 5.1
 endif
 
 ifeq "" "$(PLATFORM_SDK_VERSION)"