As long as some drivers are hard coded and undisclosed by their source its technically not possible to use them in a newer rom. I once had a talk with HondaRacer (ex-founder), who said that this was the failing part at Meizu.
The only way to solve this issue is to reverse engineer the drivers like faust93 did in CM14.1 for the Pro 5. He created his own fingerprint driver based upon a legacy one, if I am not mistaken.
In my opinion Meizu shouldn’t have used “liberal” suppliers like Samsung combined with ones created closed source drivers only as seen with the audio chip used in the Pro 5.
Some might think:
“Why doesn’t Meizu just reverse engineer their drivers?”
The answer is simple and frustrating: Because they can’t.
Reverse engineering is a relatively complex task depending on what you are trying to do. Just yesterday for instance I had to reverse engineer a part of my cars ECU software, so I could read out the PIN over my tool (was possible to flash the EEPROM). Alone this task took me around 2-3h as I was inexperienced with this.
In Meizu’s case it could be familiar. Developers might know what is inside their Flyme code, but trying to understand something you didn’t created is a hard task, especially in relation to drivers which are fairly the hardest thing you can code (see ReactOS Project as a reference).