diff --git a/build/soong/Android.bp b/build/soong/Android.bp
index 68193bc..d206b80 100644
--- a/build/soong/Android.bp
+++ b/build/soong/Android.bp
@@ -134,3 +134,20 @@ vold_hw_fde_perf {
         },
     },
 }
+
+soong_config_module_type {
+    name: "legacy_hw_disk_encryption",
+    module_type: "cc_defaults",
+    config_namespace: "twrpGlobalVars",
+    bool_variables: ["legacy_hw_disk_encryption"],
+    properties: ["cppflags"],
+}
+
+legacy_hw_disk_encryption {
+    name: "legacy_hw_disk_encryption_defaults",
+    soong_config_variables: {
+        legacy_hw_disk_encryption: {
+            cppflags: ["-DLEGACY_HW_DISK_ENCRYPTION"],
+        },
+    },
+}
diff --git a/config/BoardConfigSoong.mk b/config/BoardConfigSoong.mk
index b110898..eb8ab50 100644
--- a/config/BoardConfigSoong.mk
+++ b/config/BoardConfigSoong.mk
@@ -28,6 +28,7 @@ $(foreach v,$(EXPORT_TO_SOONG),$(eval $(call addVar,$(v))))
 
 SOONG_CONFIG_NAMESPACES += twrpGlobalVars
 SOONG_CONFIG_twrpGlobalVars += \
+    legacy_hw_disk_encryption \
     target_enforce_ab_ota_partition_list \
     target_init_vendor_lib \
     supports_hw_fde \
@@ -40,6 +41,7 @@ SOONG_CONFIG_twrpGlobalVars += \
 endif
 
 # Soong bool variables
+SOONG_CONFIG_twrpGlobalVars_legacy_hw_disk_encryption := $(TARGET_LEGACY_HW_DISK_ENCRYPTION)
 SOONG_CONFIG_twrpGlobalVars_target_enforce_ab_ota_partition_list := $(TARGET_ENFORCE_AB_OTA_PARTITION_LIST)
 SOONG_CONFIG_twrpGlobalVars_supports_hw_fde := $(TARGET_HW_DISK_ENCRYPTION)
 SOONG_CONFIG_twrpGlobalVars_supports_hw_fde_perf := $(TARGET_HW_DISK_ENCRYPTION_PERF)