The FAA and Boeing issued Emergency Airworthiness Directive 2018-23-51 on November 7th, 2018 that went to all operators of the 737 MAX worldwide, and it clearly spelled out how MCAS normally works, what can happen when the AOA sensor fails, and exactly what to do in order to immediately mitigate the problem.
(AD 2018-23-51 is located here in pdf form, read it for yourself.)
The Ethiopian Airlines pilots failed to follow the Emergency Airworthiness Directive. That is not on Boeing.
Stop buying into old propaganda.
I don’t know so many details about the first crash. But I have seen enough about the second crash. Those pilots switched off the stab switches as recommended. In doing so the electric trim switches on the yoke were disabled. Yet the trim was still froze in a position that the plane was most likely going to crash. The full manual controls were useless at this point for multiple reasons. They turned the switches back on in a desperate attempt to regain electric manual control and adjust the trim. But Mcas was wound like a rubber band at that point and it instantly crashed the plane after the stab switches were turned back on.
It is important to note that MCAS had no off switch. It never stopped trying to turn the nose down(as seen on the data recorder). The stab switches do not turn it off. They only cripple Mcas by cutting power to the electric trim motors so that they cannot be used by any command process.
The System hard numerous hardware and software design faults that even an intelligent 3rd grader could have foreseen.
Stop trying to blame the pilots. It was not their fault. And even Boeing now agrees that they are the ones at fault.