Ethereum Test: When Final Failure

Key Points

Devnet-9 combines bifurcation with fault testing. The final confirmation needs to pledge two-thirds of ETH. Blocks can still continue to be generated during the final confirmation pause. Inactive leak mechanisms can resume final confirmation. This test was limited to an isolated development network. The real testing will start after Gloas is activated.

The Glamestead devnet-9 specification released by Ethereum arranges two consecutive tasks for developers. They must first complete a clean Gloas conversion and then deliberately reduce the validator participation rate below the threshold required for final verification at the checkpoint.

The Gloas fork was originally scheduled to take place at 15:00 UTC on September 2. The same specification lists "non-final confirmation" as the second test goal for the development network, but does not confirm whether the phase has begun or ended.

The first stage is important because Gloas must be applied to large pre-bifurcation states generated at the time of creation, rather than states accumulated over days of block production. The second phase raises a more difficult question: After clients accept the new rules, can they remain consistent when Ethereum loses one of its most important security guarantees?

This order gives test value. A client can properly handle forks under normal conditions, but differences can only be exposed when the final confirmation is stalled and the network needs to be restored.

Block generation can still continue when final confirmation stops

Ethereum does not require final confirmation to maintain block production. Simply put, the final confirmation is the point in time when Ethereum treats the block as irreversible. Cancellation of a final confirmed block requires the destruction of at least one-third of the pledged ETH.

The verifier can still propose blocks, transactions can still be included, and the network can still choose a link header. Final confirmation is a stronger settlement assurance that occurs after verifiers representing at least two-thirds of the pledged ETH agree on checkpoints.

Ethereum's Proof of Equity document explains that the finally confirmed checkpoints are economically difficult to reverse. Without this status, near-term blocks are still subject to higher restructuring risks, and applications that rely on final confirmation may have to wait before activities are considered settled.

What happens when the participation rate drops below two-thirds

Parts that can proceed:

New blocks can still be proposed. Ethereum does not require final confirmation to maintain block production. Transactions can still enter these blocks. Users can submit activities while the verifier continues to select a chain head. The network can continue to move forward. Final confirmation of stagnation does not mean that the chain stops completely.

Parts that must wait for final confirmation:

No new checkpoints have received final financial confirmation. The verifier needs two-thirds of the pledged ETH to restore this guarantee. Settlement that relies on final confirmation must wait. Some bridges, exchanges, and applications rely on finalized checkpoints. Recent blocks bear higher restructuring risks. They still lack Ethereum's strongest settlement protection until final confirmation of restoration.

This test reproduces the "one-third failure boundary" discussed in Coindoo analysis-Ethereum's 33% final confirmation threshold. More than one-third of pledges fail to participate, which may prevent final confirmation even if block production continues.

How Ethereum recovers the missing absolute majority

Ethereum's recovery mechanism is called an "inactive leak." After more than four eras (approximately 25 minutes based on current network time) without final confirmation, the protocol began to gradually reduce the balance of those who did not correctly participate in the verification.

As these inactive balances decrease, the share held by active verifiers gradually increases. Once active verifiers again represent at least two-thirds of the remaining pledge amount, they can finally confirm the checkpoint and restore Ethereum's full settlement guarantee.

This process is gradual and costly for offline verifiers. During periods of stagnation, transactions may still appear in blocks, but applications that require final confirmation must wait for the network to resume. Ethereum details this mechanism in its verifier rewards and penalties documentation.

Four answers developers need to publish

A useful test report should answer four practical questions: Did the clients participating in the test apply the Gloas rules in the same way? How long has the development network been in a state without final confirmation? Does the client keep the same chain header? After recovery, when will the first checkpoint complete final confirmation?

These details will show whether the network was restored cleanly, rather than just confirming that the developer deliberately created a difficult condition.

Why it's important to do this before the Sepolia test

Final confirmation stagnation is not just a theoretical risk. In 2023, due to Prysm client issues, the Ethereum main network experienced two temporary final confirmation stagnations, although blocks continued to be generated. This development network test was a controlled attempt to restore the path before Glamsterdamm entered a broader testing phase.

Glamsterdam is still in the development network testing phase. Ethereum lists the Sepolia fork as the next milestone, which is expected to take place on September 28, while the main online line is expected to be in the fourth quarter of 2026, but a specific date has not yet been confirmed. The official GlamAmsterdam roadmap remains the reference basis for its deployment.

When developers publish results, key details will be how long the final confirmation has been stalled, whether the client remains synchronized, and which checkpoint will be the first to complete the final confirmation after recovery.