diff --git a/CleanSpec.mk b/CleanSpec.mk
index 7dac01d2bc..f4d45ff5ab 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -145,6 +145,11 @@ $(call add-clean-step, rm -rf $(PRODUCT_OUT)/obj/SHARED_LIBRARIES)
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/obj/EXECUTABLES)
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/obj/lib/*.o)
 
+# JB MR2!!!!!!!  AND *NO*, THIS WILL NOT BE K-WHATEVER.
+$(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 $(PRODUCT_OUT)/obj/APPS/*)
+
 # ************************************************
 # NEWER CLEAN STEPS MUST BE AT THE END OF THE LIST
 # ************************************************
diff --git a/core/version_defaults.mk b/core/version_defaults.mk
index eb95114a53..1162b7826d 100644
--- a/core/version_defaults.mk
+++ b/core/version_defaults.mk
@@ -41,7 +41,7 @@ ifeq "" "$(PLATFORM_VERSION)"
   # 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 := JellyBeanMR1
+  PLATFORM_VERSION := 4.2
 endif
 
 ifeq "" "$(PLATFORM_SDK_VERSION)"
@@ -53,13 +53,13 @@ ifeq "" "$(PLATFORM_SDK_VERSION)"
   # intermediate builds).  During development, this number remains at the
   # SDK version the branch is based on and PLATFORM_VERSION_CODENAME holds
   # the code-name of the new development work.
-  PLATFORM_SDK_VERSION := 16
+  PLATFORM_SDK_VERSION := 17
 endif
 
 ifeq "" "$(PLATFORM_VERSION_CODENAME)"
   # This is the current development code-name, if the build is not a final
   # release build.  If this is a final release build, it is simply "REL".
-  PLATFORM_VERSION_CODENAME := JellyBeanMR1
+  PLATFORM_VERSION_CODENAME := REL
 endif
 
 ifeq "" "$(DEFAULT_APP_TARGET_SDK)"