Real cryptocurrency mining hardware used to illustrate the Bitcoin Knots BLAKE2b chain test

Bitcoin Knots Sets Sunday Test for a BLAKE2b Breakaway Chain

By Isaac • August 29, 2026 3:06 pm • Comments

Bitcoin Knots is preparing a live rehearsal for a proposed breakaway chain that would abandon Bitcoin’s SHA-256d mining algorithm for BLAKE2b.

The test is planned for Sunday, August 30. It follows an earlier minority branch tied to BIP-110 that failed to attract enough mining support to produce blocks at anything close to Bitcoin’s normal pace.

This distinction matters: the plan does not mean the dominant Bitcoin network is changing its proof of work. It is an attempt to launch and sustain a separate chain with different consensus rules and a different mining ecosystem.

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CryptoSlate reports that Bitcoin developer Luke Dashjr told SHA-2 miners to stop mining ahead of the rehearsal. Under the announced sequence, Bitcoin Knots 29.4.1rc4 would establish the final SHA-2 block before BLAKE2b mining begins.

If the test holds, a final release could preserve that chain on September 1. If it fails, another release candidate could reset the process.

As of the report’s August 29 review, the public release page did not yet show rc4 or a final 29.4.1 build. The mainnet activation height also had not been fixed in the reviewed public materials.

CryptoSlate also found that measured testnet4 capacity was estimated at only 50 to 70 TH/s, with no public total for hash power committed to the rehearsal. That makes sustained block production the first practical test, not a guaranteed result.

Even the temporary block-weight limit still needed reconciliation: the proposal’s FAQ and pull request described 700,000 weight units, while a pinned source commit used 800,000. Nodes must enforce the same limit if they are going to stay on one ledger.

Why change the mining algorithm?

The earlier BIP-110 branch depended on miners using Bitcoin’s existing SHA-256d hardware. It separated from the dominant chain, but only a sliver of Bitcoin’s hash power followed it.

Blocks then arrived days apart instead of roughly every ten minutes.

Switching to BLAKE2b is an effort to break that dependence. The proposed network would seek miners with compatible BLAKE2b hardware instead of competing directly for the industrial SHA-256d machines securing Bitcoin.

Dashjr had already announced a BLAKE2b trial using Bitcoin Knots 29.4.1rc1 on testnet4 a week before the proposed mainnet rehearsal.

That does not solve the core coordination problem by itself. A compatible algorithm is useful only if enough miners actually point hardware at the chain and keep it there.

A chain also needs wallets, explorers, exchanges, custodians and users willing to recognize and support it.

The unresolved questions are bigger than hash rate

BLAKE2b Miner, a technical tracker focused on the proposed chain, confirmed the announced rehearsal sequence while noting that the rc4 tag and a public mainnet activation height were not yet available at its latest update.

The public materials reviewed by CryptoSlate also left important details unsettled. Those included the final activation parameters, the temporary block-weight limit and the amount of committed BLAKE2b hash power.

Wallet compatibility is another hurdle. The proposed chain would use a different block-header format, which means some lightweight clients, indexers and explorers may need changes before they can follow it reliably.

There is also replay risk. Because both networks would inherit the same pre-fork transaction history and coin balances, a transaction involving older coins could potentially be valid on both chains unless users and software apply effective replay protection.

Bitcoin Knots has discussed an opt-in signing mode, but an opt-in tool is not the same as automatic protection for every wallet.

Those are not minor launch details. They determine whether a successful mining demonstration can become a functioning network with an actual economy around it.

Sunday’s test has a narrow job

The rehearsal does not need to settle which chain deserves the Bitcoin name. Its immediate test is simpler: can the participants agree on one set of rules, produce BLAKE2b blocks and avoid another chain that crawls to a halt?

If they can, the project moves from theory to a live coordination problem for exchanges, wallets and users. If they cannot, changing the proof-of-work algorithm will have shown that hardware availability was only one part of the earlier failure.

Either way, the dominant Bitcoin network continues operating under SHA-256d. Sunday’s experiment belongs to the proposed breakaway chain, and readers should treat any resulting coins, transactions or wallet instructions as a separate network with separate risks.

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