diff --git a/config/common.mk b/config/common.mk
index 4b877c7..a4235a0 100644
--- a/config/common.mk
+++ b/config/common.mk
@@ -65,6 +65,10 @@
     vendor/bliss/prebuilt/common/bin/backuptool_ab.sh:$(TARGET_COPY_OUT_SYSTEM)/bin/backuptool_ab.sh \
     vendor/bliss/prebuilt/common/bin/backuptool_ab.functions:$(TARGET_COPY_OUT_SYSTEM)/bin/backuptool_ab.functions \
     vendor/bliss/prebuilt/common/bin/backuptool_postinstall.sh:$(TARGET_COPY_OUT_SYSTEM)/bin/backuptool_postinstall.sh
+ifneq ($(TARGET_BUILD_VARIANT),user)
+PRODUCT_SYSTEM_DEFAULT_PROPERTIES += \
+    ro.ota.allow_downgrade=true
+endif
 endif
 
 # Backup Services whitelist