diff --git a/eth/backend.go b/eth/backend.go
index e481e854e7..af03517792 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -440,6 +440,10 @@ func (s *Ethereum) StartMining() error {
 			}
 			cli.Authorize(eb, wallet.SignData)
 		}
+		// If mining is started, we can disable the transaction rejection mechanism
+		// introduced to speed sync times.
+		s.handler.enableSyncedFeatures()
+
 		go s.miner.Start()
 	}
 	return nil