diff --git a/core/dex_preopt_config.mk b/core/dex_preopt_config.mk
index ea8389a942..e36e2ebb6f 100644
--- a/core/dex_preopt_config.mk
+++ b/core/dex_preopt_config.mk
@@ -130,7 +130,7 @@ ifeq ($(WRITE_SOONG_VARIABLES),true)
   $(call add_json_str,  Dex2oatXmx,                              $(DEX2OAT_XMX))
   $(call add_json_str,  Dex2oatXms,                              $(DEX2OAT_XMS))
   $(call add_json_str,  EmptyDirectory,                          $(OUT_DIR)/empty)
-  $(call add_json_bool, EnableUffdGc,                            $(ENABLE_UFFD_GC))
+  $(call add_json_bool, EnableUffdGc,                            $(filter true,$(ENABLE_UFFD_GC)))
 
 ifdef TARGET_ARCH
   $(call add_json_map,  CpuVariant)