diff --git a/target/board/BoardConfigMainlineCommon.mk b/target/board/BoardConfigMainlineCommon.mk
index 6c56671..be7c804 100644
--- a/target/board/BoardConfigMainlineCommon.mk
+++ b/target/board/BoardConfigMainlineCommon.mk
@@ -36,9 +36,6 @@
 
 BOARD_CHARGER_ENABLE_SUSPEND := true
 
-# Enable A/B update
-AB_OTA_UPDATER := true
-
 # Enable system property split for Treble
 BOARD_PROPERTY_OVERRIDES_SPLIT_ENABLED := true
 
diff --git a/target/board/mainline_arm64/BoardConfig.mk b/target/board/mainline_arm64/BoardConfig.mk
index 8bb6212..70505f4 100644
--- a/target/board/mainline_arm64/BoardConfig.mk
+++ b/target/board/mainline_arm64/BoardConfig.mk
@@ -28,6 +28,8 @@
 
 TARGET_NO_KERNEL := true
 
+# Build generic A/B format system-only OTA.
+AB_OTA_UPDATER := true
 AB_OTA_PARTITIONS := system
 
 BOARD_VENDORIMAGE_FILE_SYSTEM_TYPE := ext4