> ## Documentation Index > Fetch the complete documentation index at: https://docs.base.org/llms.txt > Use this file to discover all available pages before exploring further. # Isthmus L2 Chain Derivation Changes > Derivation changes in the Isthmus upgrade, specifying network upgrade automation transactions executed at hardfork activation. # Network upgrade automation transactions The Isthmus hardfork activation block contains the following transactions, in this order: * L1 Attributes Transaction * User deposits from L1 * Network Upgrade Transactions * L1Block deployment * GasPriceOracle deployment * Operator Fee vault deployment * Update L1Block Proxy ERC-1967 Implementation * Update GasPriceOracle Proxy ERC-1967 Implementation * Update Operator Fee vault Proxy ERC-1967 Implementation * GasPriceOracle Enable Isthmus * EIP-2935 Contract Deployment To not modify or interrupt the system behavior around gas computation, this block will not include any sequenced transactions by setting `noTxPool: true`. ## L1Block deployment The `L1Block` contract is upgraded to support the Isthmus operator fee feature. A deposit transaction is derived with the following attributes: * `from`: `0x4210000000000000000000000000000000000003` * `to`: `null` * `mint`: `0` * `value`: `0` * `gasLimit`: `425,000` * `data`: `0x60806040523480156100105...` * `sourceHash`: `0x3b2d0821ca2411ad5cd3595804d1213d15737188ae4cbd58aa19c821a6c211bf`, computed with the "Upgrade-deposited" type, with \`intent = "Isthmus: L1 Block Deployment" This results in the Isthmus L1Block contract being deployed to `0xFf256497D61dcd71a9e9Ff43967C13fdE1F72D12`, to verify: ```bash theme={null} cast compute-address --nonce=0 0x4210000000000000000000000000000000000003 Computed Address: 0xFf256497D61dcd71a9e9Ff43967C13fdE1F72D12 ``` Verify `sourceHash`: ```bash theme={null} cast keccak $(cast concat-hex 0x0000000000000000000000000000000000000000000000000000000000000002 $(cast keccak "Isthmus: L1 Block Deployment")) # 0x3b2d0821ca2411ad5cd3595804d1213d15737188ae4cbd58aa19c821a6c211bf ``` Verify `data`: ```bash theme={null} git checkout 9436dba8c4c906e36675f5922e57d1b55582889e make build-contracts jq -r ".bytecode.object" packages/contracts-bedrock/forge-artifacts/L1Block.sol/L1Block.json ``` This transaction MUST deploy a contract with the following code hash `0x8e3fe7a416d3e5f3b7be74ddd4e7e58e516fa3f80b67c6d930e3cd7297da4a4b`. To verify the code hash: ```bash theme={null} git checkout 9436dba8c4c906e36675f5922e57d1b55582889e make build-contracts cast k $(jq -r ".deployedBytecode.object" packages/contracts-bedrock/forge-artifacts/L1Block.sol/L1Block.json) ``` ## GasPriceOracle deployment The `GasPriceOracle` contract is also upgraded to support the Isthmus operator fee feature. A deposit transaction is derived with the following attributes: * `from`: `0x4210000000000000000000000000000000000004` * `to`: `null` * `mint`: `0` * `value`: `0` * `gasLimit`: `1,625,000` * `data`: `0x60806040523480156100105...` * `sourceHash`: `0xfc70b48424763fa3fab9844253b4f8d508f91eb1f7cb11a247c9baec0afb8035`, computed with the "Upgrade-deposited" type, with \`intent = "Isthmus: Gas Price Oracle Deployment" This results in the Isthmus GasPriceOracle contract being deployed to `0x93e57A196454CB919193fa9946f14943cf733845`, to verify: ```bash theme={null} cast compute-address --nonce=0 0x4210000000000000000000000000000000000003 Computed Address: 0xFf256497D61dcd71a9e9Ff43967C13fdE1F72D12 ``` Verify `sourceHash`: ```bash theme={null} cast keccak $(cast concat-hex 0x0000000000000000000000000000000000000000000000000000000000000002 $(cast keccak "Isthmus: Gas Price Oracle Deployment")) # 0xfc70b48424763fa3fab9844253b4f8d508f91eb1f7cb11a247c9baec0afb8035 ``` Verify `data`: ```bash theme={null} git checkout 9436dba8c4c906e36675f5922e57d1b55582889e make build-contracts jq -r ".bytecode.object" packages/contracts-bedrock/forge-artifacts/GasPriceOracle.sol/GasPriceOracle.json ``` This transaction MUST deploy a contract with the following code hash `0x4d195a9d7caf9fb6d4beaf80de252c626c853afd5868c4f4f8d19c9d301c2679`. To verify the code hash: ```bash theme={null} git checkout 9436dba8c4c906e36675f5922e57d1b55582889e make build-contracts cast k $(jq -r ".deployedBytecode.object" packages/contracts-bedrock/forge-artifacts/GasPriceOracle.sol/GasPriceOracle.json) ``` ## Operator fee vault deployment A new `OperatorFeeVault` contract has been created to receive the operator fees. The contract is created with the following arguments: * Recipient address: The base fee vault * Min withdrawal amount: 0 * Withdrawal network: L2 A deposit transaction is derived with the following attributes: * `from`: `0x4210000000000000000000000000000000000005` * `to`: `null` * `mint`: `0` * `value`: `0` * `gasLimit`: `500,000` * `data`: `0x60806040523480156100105...` * `sourceHash`: `0x107a570d3db75e6110817eb024f09f3172657e920634111ce9875d08a16daa96`, computed with the "Upgrade-deposited" type, with \`intent = "Isthmus: Operator Fee Vault Deployment" This results in the Isthmus OperatorFeeVault contract being deployed to `0x4fa2Be8cd41504037F1838BcE3bCC93bC68Ff537`, to verify: ```bash theme={null} cast compute-address --nonce=0 0x4210000000000000000000000000000000000003 Computed Address: 0x4fa2Be8cd41504037F1838BcE3bCC93bC68Ff537 ``` Verify `sourceHash`: ```bash theme={null} cast keccak $(cast concat-hex 0x0000000000000000000000000000000000000000000000000000000000000002 $(cast keccak "Isthmus: Operator Fee Vault Deployment")) # 0x107a570d3db75e6110817eb024f09f3172657e920634111ce9875d08a16daa96 ``` Verify `data`: ```bash theme={null} git checkout 9436dba8c4c906e36675f5922e57d1b55582889e make build-contracts jq -r ".bytecode.object" packages/contracts-bedrock/forge-artifacts/OperatorFeeVault.sol/OperatorFeeVault.json ``` This transaction MUST deploy a contract with the following code hash `0x57dc55c9c09ca456fa728f253fe7b895d3e6aae0706104935fe87c7721001971`. To verify the code hash: ```bash theme={null} git checkout 9436dba8c4c906e36675f5922e57d1b55582889e make build-contracts export ETH_RPC_URL= # Any Ethereum L1 RPC running Cancun or Prague cast k $(cast call --create $(jq -r ".bytecode.object" packages/contracts-bedrock/forge-artifacts/OperatorFeeVault.sol/OperatorFeeVault.json)) ``` Note that this verification differs from the other deployments because the `OperatorFeeVault` inherits the `FeeVault` contract which contains immutables. So the deployment bytecode has to be executed on an EVM to get the actual deployed contract bytecode. But it sets all immutables to fixed constants, so the resulting code hash is constant. ## L1Block Proxy Update This transaction updates the L1Block Proxy ERC-1967 implementation slot to point to the new L1Block deployment. A deposit transaction is derived with the following attributes: * `from`: `0x0000000000000000000000000000000000000000` * `to`: `0x4200000000000000000000000000000000000015` (L1Block Proxy) * `mint`: `0` * `value`: `0` * `gasLimit`: `50,000` * `data`: `0x3659cfe6000000000000000000000000ff256497d61dcd71a9e9ff43967c13fde1f72d12` * `sourceHash`: `0xebe8b5cb10ca47e0d8bda8f5355f2d66711a54ddeb0ef1d30e29418c9bf17a0e` computed with the "Upgrade-deposited" type, with \`intent = "Isthmus: L1 Block Proxy Update" Verify data: ```bash theme={null} cast concat-hex $(cast sig "upgradeTo(address)") $(cast abi-encode "upgradeTo(address)" 0xff256497d61dcd71a9e9ff43967c13fde1f72d12) 0x3659cfe6000000000000000000000000ff256497d61dcd71a9e9ff43967c13fde1f72d12 ``` Verify `sourceHash`: ```bash theme={null} cast keccak $(cast concat-hex 0x0000000000000000000000000000000000000000000000000000000000000002 $(cast keccak "Isthmus: L1 Block Proxy Update")) # 0xebe8b5cb10ca47e0d8bda8f5355f2d66711a54ddeb0ef1d30e29418c9bf17a0e ``` ## GasPriceOracle Proxy Update This transaction updates the GasPriceOracle Proxy ERC-1967 implementation slot to point to the new GasPriceOracle deployment. A deposit transaction is derived with the following attributes: * `from`: `0x0000000000000000000000000000000000000000` * `to`: `0x420000000000000000000000000000000000000F` (Gas Price Oracle Proxy) * `mint`: `0` * `value`: `0` * `gasLimit`: `50,000` * `data`: `0x3659cfe600000000000000000000000093e57a196454cb919193fa9946f14943cf733845` * `sourceHash`: `0xecf2d9161d26c54eda6b7bfdd9142719b1e1199a6e5641468d1bf705bc531ab0` computed with the "Upgrade-deposited" type, with `intent = "Isthmus: Gas Price Oracle Proxy Update"` Verify data: ```bash theme={null} cast concat-hex $(cast sig "upgradeTo(address)") $(cast abi-encode "upgradeTo(address)" 0x93e57a196454cb919193fa9946f14943cf733845) 0x3659cfe600000000000000000000000093e57a196454cb919193fa9946f14943cf733845 ``` Verify `sourceHash`: ```bash theme={null} cast keccak $(cast concat-hex 0x0000000000000000000000000000000000000000000000000000000000000002 $(cast keccak "Isthmus: Gas Price Oracle Proxy Update")) # 0xecf2d9161d26c54eda6b7bfdd9142719b1e1199a6e5641468d1bf705bc531ab0 ``` ## OperatorFeeVault Proxy Update This transaction updates the GasPriceOracle Proxy ERC-1967 implementation slot to point to the new GasPriceOracle deployment. A deposit transaction is derived with the following attributes: * `from`: `0x0000000000000000000000000000000000000000` * `to`: `0x420000000000000000000000000000000000001B` (Operator Fee Vault Proxy) * `mint`: `0` * `value`: `0` * `gasLimit`: `50,000` * `data`: `0x3659cfe60000000000000000000000004fa2be8cd41504037f1838bce3bcc93bc68ff537` * `sourceHash`: `0xad74e1adb877ccbe176b8fa1cc559388a16e090ddbe8b512f5b37d07d887a927` computed with the "Upgrade-deposited" type, with `intent = "Isthmus: Operator Fee Vault Proxy Update"` Verify data: ```bash theme={null} cast concat-hex $(cast sig "upgradeTo(address)") $(cast abi-encode "upgradeTo(address)" 0x4fa2be8cd41504037f1838bce3bcc93bc68ff537) 0x3659cfe60000000000000000000000004fa2be8cd41504037f1838bce3bcc93bc68ff537 ``` Verify `sourceHash`: ```bash theme={null} cast keccak $(cast concat-hex 0x0000000000000000000000000000000000000000000000000000000000000002 $(cast keccak "Isthmus: Operator Fee Vault Proxy Update")) # 0xad74e1adb877ccbe176b8fa1cc559388a16e090ddbe8b512f5b37d07d887a927 ``` ## GasPriceOracle Enable Isthmus This transaction informs the GasPriceOracle to start using the Isthmus gas calculation formula. A deposit transaction is derived with the following attributes: * `from`: `0xDeaDDEaDDeAdDeAdDEAdDEaddeAddEAdDEAd0001` (Depositer Account) * `to`: `0x420000000000000000000000000000000000000F` (Gas Price Oracle Proxy) * `mint`: `0` * `value`: `0` * `gasLimit`: `90,000` * `data`: `0x291b0383` * `sourceHash`: `0x3ddf4b1302548dd92939826e970f260ba36167f4c25f18390a5e8b194b295319`, computed with the "Upgrade-deposited" type, with \`intent = "Isthmus: Gas Price Oracle Set Isthmus" Verify data: ```bash theme={null} cast sig "setIsthmus()" 0x8e98b106 ``` Verify `sourceHash`: ```bash theme={null} cast keccak $(cast concat-hex 0x0000000000000000000000000000000000000000000000000000000000000002 $(cast keccak "Isthmus: Gas Price Oracle Set Isthmus")) # 0x3ddf4b1302548dd92939826e970f260ba36167f4c25f18390a5e8b194b295319 ``` ## EIP-2935 Contract Deployment [EIP-2935](https://eips.ethereum.org/EIPS/eip-2935) requires a contract to be deployed. To deploy this contract, a deposit transaction is created with attributes matching the EIP: * `from`: `0x3462413Af4609098e1E27A490f554f260213D685` * `to`: `null` * `mint`: `0` * `value`: `0` * `gasLimit`: `250,000` * `data`: `0x60538060095f395ff33373fffffffffffffffffffffffffffffffffffffffe14604657602036036042575f35600143038111604257611fff81430311604257611fff9006545f5260205ff35b5f5ffd5b5f35611fff60014303065500` * `sourceHash`: `0xbfb734dae514c5974ddf803e54c1bc43d5cdb4a48ae27e1d9b875a5a150b553a` computed with the "Upgrade-deposited" type, with \`intent = "Isthmus: EIP-2935 Contract Deployment" This results in the EIP-2935 contract being deployed to `0x0000F90827F1C53a10cb7A02335B175320002935`, to verify: ```bash theme={null} cast compute-address --nonce=0 0x3462413Af4609098e1E27A490f554f260213D685 Computed Address: 0x0000F90827F1C53a10cb7A02335B175320002935 ``` Verify `sourceHash`: ```bash theme={null} cast keccak $(cast concat-hex 0x0000000000000000000000000000000000000000000000000000000000000002 $(cast keccak "Isthmus: EIP-2935 Contract Deployment")) # 0xbfb734dae514c5974ddf803e54c1bc43d5cdb4a48ae27e1d9b875a5a150b553a ``` This transaction MUST deploy a contract with the following code hash `0x6e49e66782037c0555897870e29fa5e552daf4719552131a0abce779daec0a5d`. # Span Batch Updates [Span batches](../delta/span-batches) are a span of consecutive L2 blocks than are batched submitted. Span batches contain the L1 transactions and transaction types that are posted containing the span of L2 blocks. Since [EIP-7702] introduces a new transaction type, the Span Batch must be updated to support the [EIP-7702] transaction. This corresponds with a new RLP-encoding of the `tx_datas` list as specified in [the Delta span batch spec](../delta/span-batches), adding a new transaction type: Transaction type `4` ([EIP-7702] `SetCode`): `0x04 ++ rlp_encode(value, max_priority_fee_per_gas, max_fee_per_gas, data, access_list, authorization_list)` The [EIP-7702] transaction extends [EIP-1559] to include a new `authorization_list` field. `authorization_list` is an RLP-encoded list of authorization tuples. The [EIP-7702] transaction format is as follows. * `value`: The transaction value as a `u256`. * `max_priority_fee_per_gas`: The maximum priority fee per gas allowed as a `u256`. * `max_fee_per_gas`: The maximum fee per gas as a `u256`. * `data`: The transaction data bytes. * `access_list`: The [EIP-2930] access list. * `authorization_list`: The [EIP-7702] signed authorization list. ## Activation Singular batches with transactions of type `4` must only be accepted if Isthmus is active at the timestamp of the batch. If a singular batch contains a transaction of type `4` before Isthmus is active, this batch must be *dropped*. Note that if Holocene is active, this will also lead to the remaining span batch, and channel that contained it, to get dropped. Also note that this check must happen at the level of individual batches that are derived from span batches, not to span batches as a whole. In particular, it is allowed for a span batch to span the Isthmus activation timestamp and contain SetCode transactions in singular batches that have a timestamp at or after the Isthmus activation time, even if the timestamp of the span batch is before the Isthmus activation time. [EIP-1559]: https://eips.ethereum.org/EIPS/eip-1559 [EIP-7702]: https://eips.ethereum.org/EIPS/eip-7702 [EIP-2930]: https://eips.ethereum.org/EIPS/eip-2930