contract changes following the idea of ethereum-optimism/specs#122

packages/contracts-bedrock/src/L1/SystemConfig.sol

@@ -25,8 +25,7 @@ contract SystemConfig is OwnableUpgradeable, ISemver, IGasToken {
         BATCHER,
         GAS_CONFIG,
         GAS_LIMIT,
-        UNSAFE_BLOCK_SIGNER,
-        BATCH_INBOX
+        UNSAFE_BLOCK_SIGNER
     }
 
     /// @notice Struct representing the addresses of L1 system contracts. These should be the
@@ -200,7 +199,7 @@ contract SystemConfig is OwnableUpgradeable, ISemver, IGasToken {
         _setGasLimit(_gasLimit);
 
         Storage.setAddress(UNSAFE_BLOCK_SIGNER_SLOT, _unsafeBlockSigner);
-        _setBatchInbox(_batchInbox);
+        Storage.setAddress(BATCH_INBOX_SLOT, _batchInbox);
         Storage.setAddress(L1_CROSS_DOMAIN_MESSENGER_SLOT, _addresses.l1CrossDomainMessenger);
         Storage.setAddress(L1_ERC_721_BRIDGE_SLOT, _addresses.l1ERC721Bridge);
         Storage.setAddress(L1_STANDARD_BRIDGE_SLOT, _addresses.l1StandardBridge);
@@ -357,21 +356,6 @@ contract SystemConfig is OwnableUpgradeable, ISemver, IGasToken {
         emit ConfigUpdate(VERSION, UpdateType.BATCHER, data);
     }
 
-    /// @notice Updates the batch inbox address. Can only be called by the owner.
-    /// @param _batchInbox New batch inbox address.
-    function setBatchInbox(address _batchInbox) external onlyOwner {
-        _setBatchInbox(_batchInbox);
-    }
-
-    /// @notice Updates the batch inbox address.
-    /// @param _batchInbox New batch inbox address.
-    function _setBatchInbox(address _batchInbox) internal {
-        Storage.setAddress(BATCH_INBOX_SLOT, _batchInbox);
-
-        bytes memory data = abi.encode(_batchInbox);
-        emit ConfigUpdate(VERSION, UpdateType.BATCH_INBOX, data);
-    }
-
     /// @notice Updates gas config. Can only be called by the owner.
     ///         Deprecated in favor of setGasConfigEcotone since the Ecotone upgrade.
     /// @param _overhead New overhead value.

packages/contracts-bedrock/src/L1/SystemConfigInterop.sol

@@ -63,4 +63,18 @@ contract SystemConfigInterop is SystemConfig {
             ConfigType.REMOVE_DEPENDENCY, StaticConfig.encodeRemoveDependency(_chainId)
         );
     }
+
+    /// @notice Updates the batch inbox address. Can only be called by the owner.
+    /// @param _batchInbox New batch inbox address.
+    function setBatchInbox(address _batchInbox) external onlyOwner {
+        if (_batchInbox != batchInbox()) {
+            Storage.setAddress(BATCH_INBOX_SLOT, _batchInbox);
+            OptimismPortal(payable(optimismPortal())).setConfig(
+                ConfigType.SET_BATCH_INBOX,
+                StaticConfig.encodeSetBatchInbox({
+                    _batchInbox: _batchInbox,
+                })
+            );
+        }
+    }
 }

packages/contracts-bedrock/src/L2/L1Block.sol

@@ -46,9 +46,6 @@ contract L1Block is ISemver, IGasToken {
     /// @notice The versioned hash to authenticate the batcher by.
     bytes32 public batcherHash;
 
-    /// @notice The canonical batch inbox.
-    bytes32 public batchInbox;
-
     /// @notice The overhead value applied to the L1 portion of the transaction fee.
     /// @custom:legacy
     uint256 public l1FeeOverhead;
@@ -152,7 +149,6 @@ contract L1Block is ISemver, IGasToken {
             sstore(blobBaseFee.slot, calldataload(68)) // uint256
             sstore(hash.slot, calldataload(100)) // bytes32
             sstore(batcherHash.slot, calldataload(132)) // bytes32
-            sstore(batchInbox.slot, calldataload(164)) // bytes32
         }
     }
 

packages/contracts-bedrock/src/L2/L1BlockInterop.sol

@@ -11,10 +11,12 @@ import "src/libraries/L1BlockErrors.sol";
 /// @custom:value SET_GAS_PAYING_TOKEN  Represents the config type for setting the gas paying token.
 /// @custom:value ADD_DEPENDENCY        Represents the config type for adding a chain to the interop dependency set.
 /// @custom:value REMOVE_DEPENDENCY     Represents the config type for removing a chain from the interop dependency set.
+/// @custom:value SET_BATCH_INBOX       Represents the config type for setting the batch inbox.
 enum ConfigType {
     SET_GAS_PAYING_TOKEN,
     ADD_DEPENDENCY,
-    REMOVE_DEPENDENCY
+    REMOVE_DEPENDENCY,
+    SET_BATCH_INBOX
 }
 
 /// @custom:proxied
@@ -33,6 +35,9 @@ contract L1BlockInterop is L1Block {
     /// @notice The interop dependency set, containing the chain IDs in it.
     EnumerableSet.UintSet dependencySet;
 
+    /// @notice The batch inbox address.
+    address batchInbox;
+
     /// @custom:semver +interop
     function version() public pure override returns (string memory) {
         return string.concat(super.version(), "+interop");
@@ -65,6 +70,8 @@ contract L1BlockInterop is L1Block {
             _addDependency(_value);
         } else if (_type == ConfigType.REMOVE_DEPENDENCY) {
             _removeDependency(_value);
+        } else if (_type == ConfigType.SET_BATCH_INBOX) {
+            _setBatchInbox(_value);
         }
     }
 
@@ -101,4 +108,10 @@ contract L1BlockInterop is L1Block {
 
         emit DependencyRemoved(chainId);
     }
+
+    /// @notice Internal method to set the batch inbox address.
+    /// @param _value The encoded value with which to set the batch inbox address.
+    function _setBatchInbox(bytes calldata _value) internal {
+        batchInbox = StaticConfig.decodeSetBatchInbox(_value);
+    }
 }

packages/contracts-bedrock/src/libraries/StaticConfig.sol

@@ -57,4 +57,18 @@ library StaticConfig {
     function decodeRemoveDependency(bytes memory _data) internal pure returns (uint256) {
         return abi.decode(_data, (uint256));
     }
+
+    /// @notice Encodes the static configuration data for setting a batch inbox.
+    /// @param _batchInbox Address of the batch inbox.
+    /// @return Encoded static configuration data.
+    function encodeSetBatchInbox(address _batchInbox) internal pure returns (bytes memory) {
+        return abi.encode(_batchInbox);
+    }
+
+    /// @notice Decodes the static configuration data for setting a batch inbox.
+    /// @param _data Encoded static configuration data.
+    /// @return Decoded Address of the batch inbox.
+    function decodeSetBatchInbox(bytes memory _data) internal pure returns (address) {
+        return abi.decode(_data, (address));
+    }
 }