Bitcoin’s BIP-110 appeared to stall over the weekend after nodes enforcing the proposal split from the main network and created the chain split that critics had warned about. The breakaway chain was small and stopped almost immediately.
The split started on Saturday at block 961,632, when the proposal entered its mandatory signaling window. Nodes running BIP-110 software began rejecting any block that did not signal support through version bit 4. When the first block at that height arrived without the signal, those nodes rejected it and moved onto a separate chain.
That branch barely progressed. A pseudonymous mining group called Roughnecks mined both BIP-110 blocks, 961,632 and 961,633, using Ocean’s DATUM protocol, then stopped.
By Sunday afternoon, the enforcing branch was still stuck at 961,633, while Bitcoin’s dominant chain had advanced to 961,744. That left the fork 111 blocks behind, with roughly 17 hours passing without a new block.
Support never reached the required level
The signaling data showed how little backing the proposal had. In the previous difficulty period, only 51 of 2,016 blocks signaled for BIP-110, about 2.53%. The threshold for voluntary lock-in was 55%.
After the mandatory window opened, none of the first 113 blocks on the dominant chain signaled support.
Difficulty makes the fork harder to sustain
Bitcoin’s difficulty adjustment mechanism adds another obstacle. The fork inherited the main chain’s difficulty while controlling only a negligible share of hashpower. It cannot lower mining difficulty until it completes a full 2,016-block period.
Estimates cited in the report put the time needed to finish that period anywhere from under a year to decades, depending on the hashrate assumption used.
What BIP-110 proposed
BIP-110, formally called the Reduced Data Temporary Softfork, would have capped arbitrary data in transactions for roughly a year. The proposal targeted Ordinals inscriptions and oversized OP_RETURN payloads.
Michael Saylor and Blockstream chief executive Adam Back both publicly opposed the proposal. Their objection was aimed less at the goal itself than at the activation method, which they argued invited this exact outcome.
Saylor wrote on Sunday that Bitcoin had worked as designed, putting 99.85% of hashpower on the main chain.
Ocean says affected miners will be reimbursed
Ocean, whose team backed the proposal, told clients that some miners using Ocean’s Stratum templates may have believed they were mining on Bitcoin while their hashpower was actually directed to the new BIP-110 chain.
The company said it would reimburse affected miners with the rewards they would have earned on the non-BIP-110 chain during that window.
The report was first published by Bitcoin Magazine and written by Mathew Di Salvo.