BIP-110 revival exposes replay risks as 99.85% hashrate stays on Bitcoin

The BIP-110 minority fork stalls at block 961,633 with 99.85 percent hashrate on the dominant chain, yet backers plan a BLAKE2b switch without replay protection.

"Replay protection was Spamcoin's responsibility since it's the airdrop altcoin," Luke Dashjr, a Bitcoin Core developer and BIP-110 proponent, said on X, referring to the dominant Bitcoin chain. Dashjr has repeatedly characterized the majority network as an altcoin while describing the BIP-110 branch as legitimate Bitcoin.

BIP-110, formally the Reduced Data Temporary Softfork, aimed to impose temporary consensus limits on arbitrary non-financial data in Bitcoin transactions. Supporters positioned the change as a way to reduce what they viewed as spam, such as Ordinals-style inscriptions, and to re-emphasize Bitcoin's role as money. The proposal set a 55 percent miner support threshold but peaked at roughly 2.53 percent support. On Aug. 8, at block 961,632, nodes enforcing the proposal began rejecting blocks that did not signal support, creating a chain split. Mining group Roughnecks produced the first two blocks on the minority branch before progress stalled.

Without replay protection, a transaction broadcast on one chain can remain valid on the other, meaning users who move funds during the split risk unintended transfers or double-spend complications. The proposed BLAKE2b fork, targeted around Sept. 1, would make existing SHA-256 ASIC hardware incompatible, effectively creating a separate cryptocurrency with its own mining ecosystem.

Replay Protection: Opt-In vs. Mandatory

The emerging plan does not provide automatic, full two-way replay protection. Bitcoin Knots is implementing a new sighash option that can create a transaction valid on the RDTS chain but invalid under Bitcoin Core, according to Discord discussions. Ordinary transactions may remain replayable because RDTS intends to maintain compatibility with Bitcoin Core's existing sighash types. Users wanting RDTS-specific protection would need to use the new sighash, requiring supporting wallet software or hardware-signing firmware.

Mempool.space developer Mononaut wrote on X that "the overwhelming majority of these BIP-110 minority chain blocks are just replaying days-old transactions from the main chain." The minority chain sits at block height 961,636, with additional blocks mined at an extremely slow rate. Users can also attempt to split their coins manually: a Bitcoin transaction containing data that RDTS rejects could create an output existing only on the dominant chain, while the proposed RDTS-specific sighash could produce a transaction that RDTS accepts but Bitcoin Core rejects.

The Governance Question

The episode revives familiar questions about whether miners, node operators, or economic majorities ultimately determine Bitcoin's rules. Observers note the initial outcome followed Bitcoin's design: the proposal was free to fork, yet the bulk of the network was free not to follow. The minority chain still lacks exchange listings, liquidity, and broad infrastructure.

Dashjr's position that the dominant chain is the "airdrop altcoin" collides with observable network activity. The majority network retained essentially all meaningful Bitcoin hashrate, the longest chain, weight of work, liquidity, and economic recognition. The BIP-110 proposal was subsequently marked closed, while supporters moved toward plans for the BLAKE2b change. Critics of BIP-110 had previously warned that its activation parameters raised the likelihood of precisely this kind of persistent divergence.

The decision to pursue opt-in protection rather than a universal replay barrier is unusual for a new chain with zero exchange support. Infrastructure providers are unlikely to touch a chain that chooses opt-in protection over a mandatory firewall. If the BLAKE2b fork proceeds around Sept. 1, replay protection will become a practical test of whether users can safely separate assets inherited from the same Bitcoin history. The episode demonstrates that unsuccessful upgrade campaigns can leave residual technical and coordination risks that reappear when backers refuse to abandon the branch.

This article is for informational purposes only and does not constitute investment advice.