Ethereum’s First BPO Fork Goes Live: What the Fusaka Upgrade Actually Changes

Ethereum just executed its first post-Fusaka hard fork—dubbed the BPO Fork—and the network didn't skip a beat. This isn't just another protocol tweak; it's the first major structural change enabled by last year's foundational upgrade.

Decoding the BPO Fork

Think of the Fusaka upgrade as laying down new railway tracks. The BPO Fork is the first train running on them. It implements a key governance and efficiency mechanism that was blueprinted but not activated during the original transition. The fork bypasses older consensus bottlenecks, directly cutting finality times and slashing coordination overhead for validators.

Why This Fork Matters Now

Timing is everything. With institutional staking pools growing and Layer-2 activity hitting new peaks, the network needed this operational upgrade yesterday. The BPO Fork delivers it today, optimizing resource allocation without the drama of a contentious chain split—a feat that would make a traditional corporate board blush with its efficiency.

The Bottom Line for ETH

This successful fork proves the Fusaka upgrade's architecture is more than theoretical. It demonstrates a new agility in Ethereum's development cycle, allowing targeted improvements to be deployed rapidly. For holders, it means a subtly stronger, more efficient network underpinning their assets—a technical win that, for once, doesn't require a marketing budget to explain. It's the kind of upgrade that quietly makes the system better, while Wall Street still tries to figure out how to short a blockchain.

Smooth activation with only minor issues

The Fusaka upgrade went live on mainnet at 4:49 PM ET on December 4, following the 225th All Core Developers Execution meeting. The transition was mostly smooth, though around 25% of validators running the Prysm client saw a short drop in participation. 

Fusaka is live on Ethereum mainnet!

– PeerDAS now unlocks 8x data throughput for rollups
– UX improvements via the R1 curve & pre-confirmatons
– Prep for scaling the L1 with gas limit increase & more

Community members will continue to monitor for issues over the next 24 hrs.

Developers resolved the issue quickly, and validator activity returned close to full levels. There is also a minor Nethermind-Nimbus issue under review, but developers said only a small number of users are affected. Overall, Fusaka landed cleanly, and the Ethereum chain stayed stable during the switch.

Fusaka brings new improvements meant to increase network capacity, make validator work easier, and give Layer-2 systems more room to grow. James Smith from the Ethereum Foundation said, “Fusaka is the upgrade that makes Ethereum feel bigger without looking different.” 

He explained that it gives the network more bandwidth, stronger defenses, and better wallet support while keeping the base LAYER light and decentralized.

Next steps: Automated BPO fork and Glamsterdam

The upgrade also introduces PeerDAS, a system that lets validators sample small pieces of rollup data instead of downloading full blobs, reducing bandwidth use.

Since Fusaka became active, developers have been preparing for the first automated BPO hard fork. This system automatically adjusts blob parameters and aims to make upgrades smoother and more adaptive. Work is also moving forward on the next big upgrade, Glamsterdam, where developers reviewed more than 40 proposals and cut the list down to a smaller group so the upgrade stays simple and safe.

Also Read: Farcaster’s Pivot to Wallet Sparks Debate Among crypto Community