Beacon Nodes: Historical Blobs
The Fulu consensus node upgrade in Fusaka will activate Ethereum's PeerDAS (EIP-7594), with Sepolia's upgrade on October 14th and Mainnet targeting the week of December 3rd.
Layer 2 network operators must connect to an Ethereum beacon chain node with historical blob data to ensure proper functioning of the Nitro node software, or risk failure in fetching blob data.
Impacted audiences
Required action will be required from: RPC nodes, Arbitrum One / Nova node operators, Arbitrum (Orbit) chain node operators
If you run a Nitro node and use an external L1 Ethereum beacon chain RPC URL
- Confirm that your external L1 beacon chain RPC provider has configured their L1 beacon chain node to subscribe to all subnets before the Ethereum Fusaka hard fork. For chains that post data to Ethereum Sepolia, the Ethereum Sepolia Fusaka hard fork is expected on October 14th, 2025.
- For chains that post data to Ethereum Mainnet, the Ethereum Mainnet Fusaka hard fork is expected around the first week of December 2025.
If your external L1 beacon chain RPC doesn't subscribe to all subnets:
- Switch to a provider that does before the dates above.
If you run a Nitro node and operate your own L1 Ethereum beacon chain node:
- Add the new flag (refer to specific client flags) to your beacon node's configuration before the Ethereum Fusaka hard fork. For chains that post data to Ethereum Sepolia, the Ethereum Sepolia Fusaka hard fork is expected on October 14th, 2025.
- For chains that post data to Ethereum Mainnet, the Ethereum Mainnet Fusaka hard fork is expected around the first week of December 2025.
- If you haven't added the new flag before the above deadlines, temporarily switch to an external L1 beacon chain RPC URL while your local Ethereum beacon chain node syncs up.
Ensure that the external L1 beacon chain RPC provider you're using subscribes to all subnets.
- Once your beacon chain node is fully synchronized, you can switch back to your own L1 beacon chain RPC URL (from an external L1 beacon chain RPC URL).
L1 beacon chain node flags
Prysm Consensus Layer clients
Prysm nodes have a new beacon node flag --subscribe-all-data-subnets that needs to be added to P2P options. Refer to the Prysm command-line options documentation for configuration details.
This flag is available as of Prysm v6.1.0. We recommend upgrading to the latest stable Prysm releases to ensure you have the most recent features and security updates.
Other Consensus Layer clients
Other Consensus Layer nodes also have flags to ensure they sync data from across all subnets.
The Offchain Labs team hasn't verified the accuracy of the flags below, including the corresponding versions that support these flags. Consult the respective release notes and documentation for non-Prysm consensus layer clients to ensure you're adding the correct flags.
Specific client flags
| Client | Flag |
|---|---|
| Lighthouse | --supernode |
| Teku | --p2p-subscribe-all-custody-subnets-enabled |
| Grandine | --subscribe-all-data-column-subnets |
| Lodestar | --supernode |
| Nimbus | --debug-peerdas-supernode |
Checklist
To maintain uninterrupted node operation and blob availability:
- Add the appropriate flag for your consensus layer client.
- Verify your Sepolia beacon endpoint’s configuration before October 14th.
- Verify your Mainnet beacon endpoint’s configuration before the first week of December.
- If you can't update your configuration in time, we recommend using temporary hosted beacon endpoints.