diff --git a/blockchain-configs/mainnet-prod/timer_flags.json b/blockchain-configs/mainnet-prod/timer_flags.json
index 7f2481373..0b1e9a6bb 100644
--- a/blockchain-configs/mainnet-prod/timer_flags.json
+++ b/blockchain-configs/mainnet-prod/timer_flags.json
@@ -60,7 +60,7 @@
     "has_bandage": true
   },
   "update_tx_bytes_limit": {
-    "enabled_block": null,
+    "enabled_block": 3940700,
     "has_bandage": true
   }
 }