Moreover, this could explain why Segregated Witness (SegWit), the Bitcoin protocol upgrade proposed by the Bitcoin Core development team, is blocked by some miners. Many therefore suspect the hardware manufacturer in question is Bitmain, whose CEO Jihan Wu is a staunch opponent of SegWit. 

A source familiar with the matter has confirmed to Bitcoin Magazine that this is indeed the case; though that source prefers to remain anonymous.

ASICBOOST

ASICBOOST is a patented technology developed by former CoinTerra CTO Timo Hanke and RSK Chief Scientist Sergio Damián Lerner. It takes advantage of what Maxwell described as a "vulnerability" in Bitcoin's proof-of-work system by utilizing what the ASICBOOST inventors describe as "an ingenious new way to process work items." With ASICBOOST, specialized ASIC mining chips can be up to thirty percent more efficient.

Maxwell writes that an ASIC mining device from a "major manufacturer" has been reverse engineered, which revealed that it contains undisclosed, covert use of ASICBOOST functionality. This could, Maxwell estimates, lead to as much as $100 million in increased revenue per year for a mining cartel controlling 50 percent of the network hashrate.