On October 20, Bitmain officially launched a firmware upgrade for its Antminer S9 mining rigs, enabling overt Asicboost (Overt Asicboost) functionality. The company also announced that within roughly one week, it would release similar firmware for all BM1387-based models. This move positions the Chinese mining giant alongside several other cryptocurrency mining organizations that have already begun using the once-controversial Asicboost software publicly.
Asicboost Technology: Efficiency Gains and Controversial History
Asicboost is an optimization technique that improves the efficiency of mining chips, theoretically offering up to 20-30% better performance on SHA256-based networks like Bitcoin (BTC) and Bitcoin Cash (BCH). The technology first stirred controversy in 2017 when critics alleged that Bitmain might be using it covertly. However, no concrete evidence ever emerged. Bitmain's blog post explains that its BM1387 chip had the capability to process Asicboost since April 2017, but the company refrained from activating it due to legal uncertainties around patent infringement. After seeking legal advice across multiple jurisdictions, Bitmain believes Asicboost is not currently patented—and may never be—thus deciding to enable it fully.
Firmware Update Details and Market Impact
The firmware upgrade initially targets the Antminer S9 series and will extend to all BM1387-based models. Bitmain emphasizes that the technology has “no negative impact on the Bitcoin protocol” and that its use is fully transparent—any block mined with “version-rolling” Asicboost is visibly marked in the block header. According to monitoring site Asicboost.dance, over the past week approximately 6.65% of Bitcoin network blocks were mined using overt Asicboost, representing roughly 67 version-rolled blocks and about 3.4 EH/s of hashrate (out of Bitcoin's total ~58 EH/s). Currently, seven mining pools are using the technology: Slushpool, Ckpool, Poolin, F2pool, Bitclub, Bitcoin.com, and an unknown pool.
For Bitcoin Cash, no version-rolled blocks have been observed yet, but Bitmain notes that its own pools, Btc.com and Antpool, are now also capable of using Asicboost. The company believes that widespread activation will reduce cost per terahash (J/TH) and increase overall network hashrate, making the Bitcoin network “stronger than ever before.”