Ethereum Completes Fusaka BPO Fork to Boost Layer 2 Data Availability

Ethereum Completes BPO Fork, Boosting Network Flexibility

(Source: THE BLOCK)

On January 8, 2026, Ethereum finalized the last stage of the Fusaka upgrade with the “Blob Parameters Only (BPO)” fork. This update increases the maximum number of blobs per block to 21, strengthening Layer 2 data availability and creating a more cost-effective storage environment for Rollups. The BPO mechanism enables Ethereum to gradually adjust network parameters without depending on large annual upgrades, providing a secure way to test the network’s performance limits.

How the BPO Mechanism Operates

• Phased Updates: BPO allows Ethereum to independently modify specific network parameters, like the blob target per block, minimizing risks associated with sweeping changes.
• Incremental Scaling: By gradually raising the blob target and cap per block, Ethereum safely handles higher network throughput while maintaining transaction reliability.
• Reduced Rollup Costs: As blob counts rise, Layer 2 networks benefit from improved data availability. Rollups can store transaction batches on the mainnet at lower costs, helping keep transaction fees stable.

Blobs and Layer 2 Integration

Blobs, introduced in Ethereum’s 2024 Dencun upgrade, are large binary data blocks that enable Layer 2 Rollups to record high volumes of transactions on the mainnet at minimal cost. Each blob remains on-chain for 18 days before permanent deletion. The Fusaka upgrade brings several enhancements, including PeerDAS data validation, which lets nodes sample and verify blob data, improving overall data integrity.

BPO Fork Milestones

• First BPO (December 9): Increased the target blobs per block from 6 to 10, and the maximum from 9 to 15.
• Second BPO (January 8): Raised the target blobs to 14, and the maximum to 21.

The Ethereum team notes that more blobs mean greater data availability for Layer 2 networks. Gradually raising the blob cap per block helps reduce Rollup data costs, keeps Layer 2 transaction fees low, and supports scalable network growth.

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Conclusion

The Fusaka upgrade and BPO (Blob Parameters Only) fork showcase Ethereum’s strategy for sustainable network scaling. By incrementally increasing blob limits per block, Ethereum improves Layer 2 data availability and lowers Rollup costs. This flexible, phased approach keeps transaction fees low as demand grows, ensuring the network expands securely and reliably. For developers and users, Ethereum’s ability to efficiently support more Layer 2 applications drives the ecosystem’s long-term healthy development.