What could the central bank of zimbabwe have done to stop inflation? I agree that central banks can almost always stop inflation...as long as they are controlling a reserve currency that actually has international value. Otherwise there is actually very little a central bank can do when your currency isn't used for imports, exports, international trade etc and foreign dollars/euros/RNB are needed to do almost any economical meaningful transaction.
They could have stopped flooding the country with Zimbabwean dollars and hyperinflation would have stopped immediately. Of course, the central bank of Zimbabwe was never independent from the government, but that doesn't change the fact that whoever was in charge of the monetary policy could have stopped hyperinflation at any time, had they wanted to.