Toward New Scale: Ethereum's Fusaka Upgrade

Compiled by: Whitepaper Blockchain

Key Points:

• Fusaka expands Ethereum scalability with higher Blob capacity and a more powerful PeerDAS efficient data availability system.
• L1 throughput increases significantly with a higher 60M Gas limit and execution layer optimizations.
• Improved fee mechanisms and UX upgrades lay the foundation for a more unified and cost-effective L1-L2 ecosystem.

Fusaka Overview

Ethereum’s next upgrade, codenamed “Fusaka” hard fork, is scheduled for December 3, 2025 at 21:49 UTC (slot 13,164,544). Fusaka combines the execution layer upgrade Osaka and the consensus layer upgrade Fulu, following the architecture of past forks.

Following Pectra in May, Fusaka makes an important step in the Ethereum scaling roadmap, enhancing Layer-1 performance, expanding Blob capacity, increasing Rollup cost efficiency, and delivering UX upgrades. It also introduces the Blob Parameter Only (BPO) fork, a way to safely increase Blob capacity as Rollup demand grows. Earlier this year, the Ethereum Foundation outlined its “protocol” strategy focused around three long-term goals: scaling L1, scaling Blobs, and improving UX. Fusaka is the first upgrade fully aligned with this unified vision, marking a turning point in how Ethereum plans for scale and accessibility improvements in the future.

Scaling Blobs

Last year’s Decun upgrade introduced efficient “Blobs”, an economical way for Rollups to store transaction data on Ethereum mainnet. Since then, Blobs have seen heavy use, driven by Rollups like Base, Arbitrum, and Lighter. This has led Blob usage to approach its peak (currently near the target of 6 Blob blocks per block), creating the risk of an exponential surge in Rollup demand. Higher data availability (DA) requirements have made Blob space a key bottleneck on Ethereum’s scaling path, and Fusaka directly addresses these limitations.

PeerDAS: Peer Data Availability Sampling

PeerDAS (EIP-7594) or Peer Data Availability Sampling is arguably the most important upgrade in Fusaka, directly addressing the goals of scaling L1 and Blobs. PeerDAS introduces a more efficient way for Ethereum nodes to check Blob data availability. Instead of full nodes downloading entire Blobs, they sample small fragments of data to verify data availability, providing the same security guarantees without increasing the load on L1 relay nodes.

Expected Impacts:

• Nodes only store about 1/8 of each Blob, enabling much greater Blob throughput without increased hardware requirements.
• Allows Ethereum to safely increase Blob capacity, a key driver of Rollup capacity.
• Internal data availability costs lead to cheaper L2 transactions and more reliable batch posting.
• Lays the groundwork for full Danksharding and higher overall transaction throughput across the ecosystem. For example, Base stated in a blog post that post-Fusaka L2 scalability improvements would allow them to “double their chain throughput within 2 months.”

Blob Parameter Only (BPO) Fork

With PeerDAS reducing the bandwidth and storage needed by nodes to verify Blob data, Ethereum can now safely increase Blob capacity. Fusaka introduces the Blob Parameter Only (BPO) fork, aiming to gradually increase the number of Blobs per block over time. This allows Ethereum to tune Blob parameters without waiting for a full hard fork, giving the protocol a more flexible, responsive scaling tool.

Upcoming BPO Forks:

• Early 2026: Increase from 6 to 12 (slot 14,000,000)
• Late 2026: Increase from 12 to 25 (slot 15,500,000)
• Early 2027: Increase from 25 to 50 (slot 16,300,000)

Expected Impacts:

• More DA bandwidth: Rollup capacity increases from 6 Blobs per block to 128 Blobs, and reduces L2 transaction fees.
• Flexible scaling: Blob parameters can be dynamically adjusted as demand grows.
• Gradual development path: Aligns with Ethereum’s roadmap for cheaper Rollup execution and scalable data availability.

Blob Base Fee Adjustment

As Blob capacity expands, Ethereum’s Blob fee market will play a larger role in matching Rollup demand. Currently, Rollup consumption on Blobs is almost zero. Since Blob prices typically stay at the 1 wei minimum, demand is relatively price-insensitive and doesn’t always adjust smoothly as usage changes. This leaves fee mechanics stuck in a “inelastic” zone, limiting its ability to respond to usage fluctuations.

Fusaka introduces a lower bound for the Blob base fee by partially linking it to the L1 base fee. This prevents the Blob price from falling to zero and keeps the fee adjustment mechanism intact as Blob space expands.

• More stable Blob pricing: Prevents the fee market from dropping to the floor.
• Predictable Rollup economics: Ensures Rollups pay a reasonable baseline for data availability, without sudden or unstable fee jumps.
• Minimal impact on user costs: Even with the new lower bound, L2 data costs remain only a few cents, with negligible impact on user experience.
• Sustainable long-term economics: As node processing scales with increased Blob throughput, Blob fees adaptively contribute to ETH and may do so more over time as capacity expands.

Scaling L1

Fusaka also places strong emphasis on L1 scaling. It increases Ethereum’s Layer-1 execution capacity through EIP-7935, raising the protocol’s default Gas limit to 60M. This directly raises the number of transactions that can fit in a block, resulting in higher throughput, less congestion, and cheaper Gas fees.

Expected Impacts:

• Higher throughput: More computation per block increases total L1 capacity.
• Support for more complex applications: Larger Gas limits support complex contract execution.
• Less front-running congestion under load: Extra space reduces pre-block congestion during demand spikes.
• Helps keep fees low: Extra capacity supports the current low fee environment (<0.4 gwei).

In addition to the increased Gas limit, Fusaka introduces improvements to make L1 execution clearer and prepare the network for future scaling. A new per-transaction Gas usage cap prevents any single transaction from dominating a block and lays the groundwork for parallel execution. Updates to ModExp precompile retune Gas costs and set clearer boundaries for operations, keeping resource usage predictable as throughput grows. The network layer is simplified by removing outdated pre-merge fields, making Ethereum node syncing faster and more convenient.

Improved User Experience

Fusaka also introduces updates improving user and developer usability. EIP -7951 adds native support for the secp256r1 elliptic curve, the signature standard used by Apple Secure Enclave, Android Keystore, and most consumer hardware. This allows wallets and applications to directly integrate familiar authentication flows (Face ID, Touch ID, WebAuthn) into Ethereum, reducing onboarding friction and enhancing security for retail and institutional users.

These upgrades help modernize Ethereum’s developer and user interfaces, making it easier to build secure, mainstream-ready applications.

Conclusion

With Fusaka’s activation, the most immediate impacts will be lowered Rollup costs up front, higher Blob throughput, and significant expansion of L1 execution capacity. At the same time, expanded Blob space, reduced overhead, and ongoing L1 performance improvements will shape L2 settlement economics and related dynamics, streamlining the broader Ethereum ecosystem’s internal aggregation.

While long-term value ultimately depends on demand and adoption, Fusaka lays a clearer, more scalable foundation for Ethereum’s next phase, in which L1 and L2 functions operate more seamlessly together and the network is better positioned to support higher-capacity users, assets, and on-chain activity.

Original link: https://www.hellobtc.com/kp/du/12/6151.html

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