Proposal Title: Absolute Prestate Updates for Isthmus Activation & Blob Preimage Fix
Proposal Type: Maintenance Upgrade
Executive Summary
Hi, I’m Seb, a Protocol Software Engineer at OP Labs. I prepared this proposal in collaboration with Paul Dowman, and Lewej Whitelow from the OP Labs Team.
Neither OP Labs nor I or any other entity mentioned represent or speak on behalf of the Optimism Foundation.
This proposal aims to update the absolute prestates on OP Mainnet, Ink, Unichain, and Base to set the activation times for the Isthmus hard fork to Fri May 9 16:00:01 UTC 2025, and to fix the incorrect blob preimages bug.
Motivation
Upgrade Proposal #15 was ratified contingent upon updating the absolute prestate with the activation time of the Isthmus hard fork (see Action Plan). This proposal introduces the prestate that includes this activation time. The opportunity is also taken to fix the incorrect blob preimages bug.
Specifications
Blockspace Charter
No changes to the Standard Rollup Charter are required for this upgrade.
Technical details
At the time of this proposal the version of op-program with Isthmus hardfork times is 1.6.0-rc.2. The absolute prestate hash (cannon64 variant) is 0x03682932cec7ce0a3874b19675a6bbc923054a7b321efc7d3835187b172494b6. Note that this is the 64-bit version because Upgrade 14 upgraded Cannon to 64-bit. It has been publicly verified here.
The changes to op-program also include a fix for the incorrect blob preimages bug.
The full diff from 1.5.0 to 1.6.0-rc.2 can be inspected here.
Impact summary (a comprehensive description of the consequences of adopting the proposed changes).
The impact is the same as described in Upgrade Proposal #15 - Isthmus Hard Fork with Isthmus activating on Fri May 9 16:00:01 UTC 2025. Additionally, the incorrect blob preimages bug is fixed and any potential risk from it is mitigated from the moment this upgrade is executed.
Precommitment impact review
- Collective Fee Take: no modification or onchain implementation introduced.
- Governor/Servicer Role Separation: no change to role structures or authorization patterns.
- Ossified GasLimits: no changes to ossified gasLimits
- Direct Fee Margin Controls: no change to the relevant configuration structure and authorization. Some helper methods for get/set logic are added to the SystemConfig, but do not fulfill the overall intent of this precommittment.
Action Plan
All users need to upgrade their nodes by the time that Isthmus activates:
Additionally, chain operators need to upgrade their batchers and challengers
Superchain-ops task are being written (OP+Ink, Unichain) to update the absolute prestate hashes of the dispute game systems of OP Mainnet, Ink and Unichain. Base is preparing their own upgrade tasks. They use the same OPCM contract as Upgrade 14, and call the updatePrestate function on it to update the prestate hashes by deploying new FaultDisputeGame and PermissionedDisputeGame contracts with the updated prestate hashes and setting the new game contract addresses on the DisputeGameFactory.
After the Veto Period of this proposal has passed, signatures will be collected for execution of the superchain-ops tasks. The multisig transaction payloads that will be sent by the respective ProxyAdminOwner s are
-
Transaction payload for OP Mainnet & Ink PAO (
0x5a0Aae59D09fccBdDb6C6CcEB07B7279367C3d2A)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 -
Transaction payload for Unichain PAO (
0x6d5B183F538ABB8572F5cD17109c617b994D5833)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
and they can be verified by following the steps in the tasks’ VALIDATION.md files.
Ethereum has scheduled Pectra to activate on May 7. Contingent on this upgrade activating successful, we will execute the task on May 7 or 8, 1-2 days before Isthmus is set to activate.
Conclusion
This maintenance upgrade sets the activation time for the Isthmus hard fork to May 9, 2025, at 16:00:01 UTC, and includes a critical fix for the blob preimages bug. The upgrade aligns with Ethereum’s Pectra activation schedule and will be executed following standard operational procedures. This timing ensures a smooth transition while maintaining the security and reliability of the OP Mainnet network.
We appreciate your support in approving this upgrade, which will ensure the continued stability and advancement of OP Mainnet through the Isthmus hard fork.
