What did Fusaka change on ETH?

TLDR

Fusaka changed Ethereum (ETH) by activating PeerDAS, raising L1 capacity, and adding security and UX features focused on rollup scaling without sacrificing decentralization, live as of 3 Dec (21:49 UTC) per an upgrade report.

1. PeerDAS enables sampled blob verification and up to 8x blob throughput, lowering L2 fees and validator load, confirmed in an official thread.
2. L1 gas limit increased to 60M (~33% more throughput) and a per?transaction cap near 16.8M gas for stability per a market update.
3. New features: secp256r1 precompile, deterministic proposer lookahead, and CLZ opcode; blob fee tuning adds a fee floor per an upgrade note.

Deep Dive

1. PeerDAS And Blobs

PeerDAS (EIP?7594) lets validators sample small parts of L2 data blobs instead of downloading full blobs, cutting bandwidth and enabling more blob capacity.

1. Ethereums thread highlights PeerDAS, blob scaling, and a staged blob?parameter?only schedule that lifts blob counts (target 6 now; to 10 on 9 Dec; to 14 on 7 Jan 2026) in the post above.
2. News coverage emphasizes PeerDAS reduces validator and L2 load, speeding settlement and lowering costs in a protocol explainer.
3. Activation was smooth at 21:49 UTC and finalized in ~15 minutes, per the upgrade report.

2. Gas Limit And Transaction Cap

Fusaka raises L1s block gas limit to 60M, boosting throughput, while setting a single?transaction cap near 16.8M gas to prevent one tx from swallowing a block.

1. The increased 60M gas target and safety checks are noted in the Ethereum thread.
2. The ~16.8M per?transaction limit (EIP?7825) and node preparations are detailed in a market update.

3. Security And UX Additions

Fusaka adds secp256r1 signature support, proposer lookahead, and the CLZ opcode, and introduces blob fee tuning to strengthen economics and UX.

1. secp256r1 precompile (EIP?7951), deterministic proposer lookahead (EIP?7917), and CLZ opcode (EIP?7939) are listed in the official thread.
2. A minimum blob base fee (EIP?7918) helps stabilize rollup fees and ETH burn dynamics per a coverage note.

Conclusion

Fusaka is a targeted scaling upgrade that makes Ethereum more capable of settling growing L2 activity: PeerDAS reduces data burdens, higher L1 gas lifts capacity, and fee tuning reinforces economics. The result should be progressively lower rollup costs and faster throughput, with safeguards that preserve decentralization and validator accessibility.