diff --git a/core/android_soong_config_vars.mk b/core/android_soong_config_vars.mk
index 6e521950ee..cdd48e7cc6 100644
--- a/core/android_soong_config_vars.mk
+++ b/core/android_soong_config_vars.mk
@@ -78,7 +78,8 @@ INDIVIDUALLY_TOGGLEABLE_PREBUILT_MODULES := \
   wifi \
 
 $(foreach m, $(INDIVIDUALLY_TOGGLEABLE_PREBUILT_MODULES),\
-  $(call soong_config_set,$(m)_module,source_build,$(MODULE_BUILD_FROM_SOURCE)))
+  $(if $(call soong_config_get,$(m)_module,source_build),,\
+    $(call soong_config_set,$(m)_module,source_build,$(MODULE_BUILD_FROM_SOURCE))))
 
 # Apex build mode variables
 ifdef APEX_BUILD_FOR_PRE_S_DEVICES