diff --git a/contracts/deploy/Factory.sol b/contracts/deploy/Factory.sol
index 2408a58..525ea4a 100644
--- a/contracts/deploy/Factory.sol
+++ b/contracts/deploy/Factory.sol
@@ -67,7 +67,7 @@ contract Factory is Controlled {
             // by using o_code = new bytes(size)
             o_code := mload(0x40)
             // new "memory end" including padding
-            mstore(0x40, add(o_code, and(add(add(size, 0x20), 0x1f), bnot(0x1f))))
+            mstore(0x40, add(o_code, and(add(add(size, 0x20), 0x1f), not(0x1f))))
             // store length in memory
             mstore(o_code, size)
             // actually retrieve the code, this needs assembly