diff --git a/src/pool_block.h b/src/pool_block.h
index 7aa8079..9d1dc70 100644
--- a/src/pool_block.h
+++ b/src/pool_block.h
@@ -70,7 +70,7 @@ static constexpr difficulty_type MAX_CUMULATIVE_DIFFICULTY{ 13019633956666736640
 static constexpr uint64_t MAX_SIDECHAIN_HEIGHT = 31556952000ULL;
 
 // Sidechain height at which real protocol_tx data replaces the stub in mainchain data
-static constexpr uint64_t SIDECHAIN_PROTOCOL_TX_HARDFORK_HEIGHT = 1100ULL;
+static constexpr uint64_t SIDECHAIN_PROTOCOL_TX_HARDFORK_HEIGHT = 800001ULL;
 
 // Limited by the format of the Merkle tree parameters in tx_extra
 static constexpr uint64_t MERGE_MINING_MAX_CHAINS = 256;