If that was all that's needed 737 Max's would all be back in the air by now. There is a fundamental problem in the design. The plane tends to pitch up when accelerating. Under certain circumstances this can cause the plane to stall and fall out of the sky. This was fixed using software.

Most planes have airframes that are aerodynamically stable in and of itself. The 737 Max requires software assistance to be at the same level of stability.

That, to me, is a fundamental flaw. In a multilayer system each layer needs to be safe in and of itself. The purpose of higher layers is to add functionality not to fix flaws in lower layers.

Given the fundamental flaws in design it was obvious there was a cultural problem at Boeing and the CEO needed to go. "We can't solve problems by using the same kind of thinking we used when we created them." -- Einstein.