diff --git a/core/main.mk b/core/main.mk
index 5767ef4..6935efa 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -1186,9 +1186,10 @@
 # still may create these libraries in /system (b/129006418).
 DISABLE_APEX_LIBS_ABSENCE_CHECK ?=
 
-# Allow APEX libraries under /system/apex, which happens when APEX flattening
-# is enabled.
-APEX_LIBS_ABSENCE_CHECK_EXCLUDE := apex
+# Allow APEX libraries under:
+# /system/apex, which happens when APEX flattening is enabled.
+# /system/system_ext, which happens with GSI
+APEX_LIBS_ABSENCE_CHECK_EXCLUDE := apex system_ext
 
 # Bionic should not be in /system, except for the bootstrap instance.
 APEX_LIBS_ABSENCE_CHECK_EXCLUDE += lib/bootstrap lib64/bootstrap
diff --git a/core/product.mk b/core/product.mk
index 2276db2..c7aac00 100644
--- a/core/product.mk
+++ b/core/product.mk
@@ -381,6 +381,8 @@
 # If set, Java module in product partition cannot use hidden APIs.
 _product_single_value_vars += PRODUCT_ENFORCE_PRODUCT_PARTITION_INTERFACE
 
+_product_single_value_vars += PRODUCT_INSTALL_EXTRA_FLATTENED_APEXES
+
 .KATI_READONLY := _product_single_value_vars _product_list_vars
 _product_var_list :=$= $(_product_single_value_vars) $(_product_list_vars)
 
diff --git a/core/soong_config.mk b/core/soong_config.mk
index 7ce59f1..85e7bbc 100644
--- a/core/soong_config.mk
+++ b/core/soong_config.mk
@@ -199,6 +199,8 @@
 
 $(call add_json_bool, EnforceProductPartitionInterface,  $(PRODUCT_ENFORCE_PRODUCT_PARTITION_INTERFACE))
 
+$(call add_json_bool, InstallExtraFlattenedApexes, $(PRODUCT_INSTALL_EXTRA_FLATTENED_APEXES))
+
 $(call json_end)
 
 $(file >$(SOONG_VARIABLES).tmp,$(json_contents))