corrupt firmware

I want to downgrade from 5.6.3.29 beta to Flyme 5.1.9.0G. But everytime when i try it an error show up: corrupt firmware. ,
So I plugged my Phone in, put my Phone on (volume up + on button),I downloaded version Flyme 5.1.9.0G. (update.zip), Put it in the recovery folder, and clear + update my Phone. but the error corrupt fireware show up. does someone have a solution?

Meizu Pro 5

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Meizu Pro 5

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