Flyme account doesn't apply root privileges

Hi! I just received my meizu m2 mini from gearbest. It has been delivered with FlymOS 4.5.3C version. I opened flyme account, and it has been automaticlly setup for OPEN System privileges, but root checker always reports “sorry! root access is not properly installed on this device”.
What i’m trying to do is replace 4.5.3C version with one of the “I” versions. Can you please tell me which one is working best, and is there an alternative way to implement it? Thanks!

T

Looks like your connection to Meizufans was lost, please wait while we try to reconnect.