diff --git a/Makefile b/Makefile
index 344d08ec..edd287ad 100644
--- a/Makefile
+++ b/Makefile
@@ -48,7 +48,7 @@ PCKRetrievalTool: QuoteGeneration
 	$(MAKE) -C tools/PCKRetrievalTool
 
 SGXPlatformRegistration:
-	$(MAKE) -C tools/SGXPlatformRegistration
+	$(MAKE) -j1 -C tools/SGXPlatformRegistration
 
 WinPle:
 	$(MAKE) -C driver/win/PLE
diff --git a/tools/PCKCertSelection/Makefile b/tools/PCKCertSelection/Makefile
index c1115feb..fbdfa06c 100644
--- a/tools/PCKCertSelection/Makefile
+++ b/tools/PCKCertSelection/Makefile
@@ -82,7 +82,7 @@ $(PROJECTS): $(BIN_DIR)
 $(BIN_DIR):
 	$(PCKCERTSEL_VERBOSE)mkdir -p $@
 
-$(ZIPFILE):
+$(ZIPFILE): $(PROJECTS)
 	bash pack.sh
 	$(PCKCERTSEL_VERBOSE)echo "$@ : done"
 	$(PCKCERTSEL_VERBOSE)echo