diff --git a/dx/Android.mk b/dx/Android.mk
index d13e291..c0e10a1 100644
--- a/dx/Android.mk
+++ b/dx/Android.mk
@@ -61,7 +61,7 @@
 
 $(LOCAL_BUILT_MODULE): PRIVATE_PROGUARD_FLAGS:= \
   -include $(addprefix $(LOCAL_PATH)/, shrinkedAndroid.proguard.flags)
-$(LOCAL_BUILT_MODULE): $(call java-lib-files,android_stubs_current) \
+$(LOCAL_BUILT_MODULE): $(call java-lib-files,sdk_v20) \
                        $(addprefix $(LOCAL_PATH)/, shrinkedAndroid.proguard.flags)| $(PROGUARD)
 	@echo Proguard: $@
 	$(hide) $(PROGUARD) -injars "$<(**/*.class)" -outjars $@ $(PRIVATE_PROGUARD_FLAGS)
diff --git a/dx/shrinkedAndroid.proguard.flags b/dx/shrinkedAndroid.proguard.flags
index c22ec92..d248a4a 100644
--- a/dx/shrinkedAndroid.proguard.flags
+++ b/dx/shrinkedAndroid.proguard.flags
@@ -5,20 +5,36 @@
 -dontpreverify
 -keep public class * extends android.app.Instrumentation {
 }
+-keep public class android.app.Instrumentation {
+}
 -keep public class * extends android.app.Application {
 }
+-keep public class android.app.Application {
+}
 -keep public class * extends android.app.Activity {
 }
+-keep public class android.app.Activity {
+}
 -keep public class * extends android.app.Service {
 }
+-keep public class android.app.Service {
+}
 -keep public class * extends android.content.ContentProvider {
 }
+-keep public class android.content.ContentProvider {
+}
 -keep public class * extends android.content.BroadcastReceiver {
 }
+-keep public class android.content.BroadcastReceiver {
+}
 -keep public class * extends android.app.backup.BackupAgent {
 }
+-keep public class android.app.backup.BackupAgent {
+}
 -keep public class java.lang.annotation.Annotation {
 }
 -keep public class * extends android.test.InstrumentationTestCase {
 }
+-keep public class android.test.InstrumentationTestCase {
+}