Yeah but nobody has evidence that bitmain was running the firmware fix before they released it publicly so it's all speculation. Hanlon's Razor would indicate incompetence over malice.

nostr:npub1ag5y3zm9n2myxvt8e5pyadewqx3httqhee22rnwxuhww9ake8y3slsekr3 reverse engineered the firmware and he shares this opinion. Apparently the code is less than great. 😅

It may be possible to produce a statistical argument that bitmain mines less empty blocks based on blockchain data. But I don't think assuming a conspiracy is productive. Not defending Bitmain, they are the biggest threat to bitcoin IMO.