> Definitely something to do with the chip that brother checks... There is nothing "definitely" about that; you could have just replaced a defective, knockoff

> Definitely something to do with the chip that brother checks... There is nothing "definitely" about that; you could have just replaced a defective, knockoff or recycled chip that doesn't work: the grey market for ICs is absolutely rampant and full of trash. Replacing the chip doesn't prove some firmware check. All of the popular, disposable ICs used in mass market products like toner cartridges are cloned and/or recycled and are widely available at low cost, and problems with these are common.