The blame here seems to be solely on Boeing's shoulders. They originally submitted FAA cert docs that mentioned the MCAS system could only manipulate the tail by 0.6 degrees. They then realized that 0.6 was not sufficient and decided to reprogram it allow for a 2.5 degree manipulation without letting the FAA know (atleast that is what the article implies). So the FAA certified the plane on an assumption that MCAS would move the plane by +/- 0.6 degrees and in reality was doing +/- 2.5 degrees. That is half the total movement and in flight terms a lot! Yes the FAA didn't double check, but looks like Boeing manipulated - maybe just like VW did with the emissions scandals to fool the inspectors and the inspection.
Article Source -
https://www.seattletimes.com/busines...ion-air-crash/