diff --git a/contracts/governance/src/ZeroExTimelock.sol b/contracts/governance/src/ZeroExTimelock.sol
index a397ac2055..93f28c71e5 100644
--- a/contracts/governance/src/ZeroExTimelock.sol
+++ b/contracts/governance/src/ZeroExTimelock.sol
@@ -64,7 +64,7 @@ contract ZeroExTimelock is TimelockController {
             // function signature for rollback(bytes4,address)
             // = bytes4(keccak256("rollback(bytes4,address)"))
             // = 0x9db64a40
-            require(payload.readBytes4(0) == 0x9db64a40, "TimelockController: Not a rollback call");
+            require(bytes4(payload) == bytes4(0x9db64a40), "TimelockController: Not a rollback call");
 
             _execute(target, value, payload);
             emit CallExecuted(id, i, target, value, payload);