Bitmain has introduced a new firmware upgrade for its Antminer S9 mining machines, enabling users to activate overt Asicboost while mining SHA256-based cryptocurrencies. The company said the release marks the beginning of a wider rollout, with firmware support for all BM1387-based models expected roughly one week later. The move places Bitmain more firmly alongside a growing group of mining operators and pools that have been openly using the once-controversial optimization method.
Bitmain Opens Asicboost to Antminer Users
According to the company, the updated S9 firmware allows miners to use overt Asicboost on networks such as Bitcoin (BTC) and Bitcoin Cash (BCH). Asicboost has long attracted attention because of its potential to improve mining performance. The report notes that the technology can deliver roughly 20% to 30% better efficiency in block processing compared with mining hardware that does not use the protocol.
Asicboost became a flashpoint in industry debates in 2017, when critics argued that the optimization might be used covertly and provide unfair advantages. Bitmain was among the companies accused by some BTC supporters of stealthily benefiting from the method, but the article emphasizes that such claims were never proven. It also notes that no other mining pools were caught using the protocol covertly after the broader public controversy took shape.
Bitmain said it had already disclosed in April 2017 that its BM1387 ASIC chips were technically capable of processing Asicboost. At the time, however, the company refrained from activating the functionality because of legal uncertainty. Specifically, Bitmain cited potential patent issues and the risk of infringing third-party intellectual property rights as reasons for avoiding deployment earlier.
In its explanation, the firm said it initially decided not to enable this mathematical function in mining hardware because it did not want to violate patent law or act improperly while legal questions remained unresolved. Instead, Bitmain said it chose to continue focusing on research and development and on improving the efficiency of its mining chips through conventional engineering advances.
From Controversial Technique to Transparent Deployment
The latest announcement signals that Bitmain now sees the legal landscape differently. The company said it sought legal advice across multiple jurisdictions and came to the view that Asicboost is not currently patented in an enforceable way and may never be officially patented. That assessment appears to have cleared the path for a public rollout to customers rather than a limited or internal use of the feature.
Bitmain stressed that the implementation is overt, meaning it is transparent and visible on-chain. The company said the use of the optimization can be identified directly in the block header of any version-rolling boosted blocks. It also argued that the technology has no negative impact on the Bitcoin protocol, positioning the update as a straightforward efficiency improvement rather than a controversial shortcut.
From Bitmain’s perspective, the upgrade gives customers a direct operating advantage. By activating Asicboost, miners using supported hardware can reduce their energy cost per unit of work and potentially improve profitability in a highly competitive mining environment. The company also framed the move as beneficial beyond individual operators, arguing that broader use of the technology could lower the J/TH cost of mining and contribute to greater total network hashpower.
Bitmain’s public stance was especially notable because it linked this firmware release to a wider narrative about network strength. In the company’s view, a more efficient mining fleet could help reinforce the security and resilience of the Bitcoin network by increasing aggregate processing power.
Adoption of Overt Asicboost Has Been Growing
The article points out that Bitmain’s firmware launch is not happening in isolation. Overt Asicboost had already been adopted by a number of mining pools for months before this firmware announcement. Citing data from Asicboost.dance, the report said that during the previous week, about 6.65% of blocks on the BTC network were mined using overt Asicboost. That amounted to roughly 67 version-rolled blocks.
In hashrate terms, those blocks represented about 3.4 EH/s out of a total BTC network hashrate of approximately 58 EH/s at the time. Those figures suggest that while overt Asicboost was far from dominant, it had already moved beyond niche use and become a meaningful part of the mining landscape. The article listed several pools associated with Asicboost mining activity, including Slushpool, Ckpool, Poolin, F2pool, Bitclub, Bitcoin.com, and an unknown pool.
Bitmain also said that, in addition to firmware support for BM1387-based hardware, mining pools Btc.com and Antpool were now able to utilize Asicboost. That matters because software support at the device level is only part of the adoption equation; effective use also depends on mining pool infrastructure and coordination around version-rolling block templates.
Questions Remain Around BCH Adoption
Even with Bitmain opening the feature to Antminer owners, the article noted that it remained unclear whether miners on the Bitcoin Cash network would make meaningful use of Asicboost going forward. At the time of publication, there was no data showing version-rolled blocks on the BCH chain. That left open the question of whether support in theory would translate into operational uptake in practice.
The uncertainty reflects a broader reality of mining technology adoption: technical compatibility does not always produce immediate network-wide usage. Miner preferences, pool support, profitability conditions, and ecosystem politics can all affect whether a feature is embraced quickly or only gradually.
Still, Bitmain’s decision was important because of the company’s large installed base and influence in the ASIC mining market. Once firmware support is made available to a widely deployed machine like the Antminer S9, any optional optimization can spread quickly if miners decide the gains are worth the operational change. In this case, the reported 20% to 30% efficiency advantage gives operators a strong incentive to at least evaluate the upgrade.
A Shift in Industry Tone
Perhaps the most significant takeaway from the announcement is the change in how Asicboost is being discussed. What was once framed primarily as a disputed and opaque tactic is increasingly being described as a transparent, measurable optimization layer that miners can adopt openly. Bitmain’s use of the word “overt” is central to that repositioning: the company is not merely adding a performance feature, but also signaling that it sees transparency as part of the answer to earlier criticism.
Whether that shift fully resolves old concerns is another matter, but the direction is clear. As mining margins tighten and hardware competition intensifies, efficiency enhancements that were once politically sensitive may become normalized if they are implemented publicly and accepted by major ecosystem players. Bitmain’s firmware release for the Antminer S9 therefore represents more than a product update; it reflects a broader maturation in how mining optimizations are presented, scrutinized, and adopted across the Bitcoin sector.