@MeizuMX5isBAD I recommend you to take a look at our Wiki’s article how to up/downgrade:
Just follow method 2 to install the chinese firmware.
You can either use Flyme 5 or Flyme 6 (links will directly link to the firmware).
Please be sure to wipe your data when changing from a G to an A firmware. Please also keep in mind that this will cause your apps to be deleted, however personal data won’t be affected by this.
After you have successfully booted up your device, you will be told to setup your phone. The only languages available are Chinese (traditional and simplified) and English. As I suppose you want to use a language other than that, just complete the setup.
As soon as you have done this you have to put the device into Chinese again over the Settings and then enter Fingerprint & security. There should be an option called root.
In case you cannot remember the interface so well, I recommend making screenshots while the phone is in english.
Important! You need to be logged in while doing this.
As soon as you accepted the ToS on the rooting menu you will be prompted to enter your password. The device then will reboot.
Now you can put everything back to english and download the GSM Installer from the AppCenter. Complete its installation and then log into Google Play. Search for an app called “morelocale2”. Open it, grant it root privileges and select your desired language.