Ex File System

adnan

Umi Z does not support SD card in Exfat file system , Umi dev team must add its support in future updates.

Medard22

Not only Umi Z but a whole lot of other phones had issues with exFAT. The vFAT used for sdcard is okay-ish, unless you work with the big files over 4GB regularly.

adnan

But many of the phone supported exFAT, my two years old honor 5X support it.

Medard22

Yeah you are right. I haven´t tried the Nougat beta, perhaps the exFAT support is working in there. We could ask in the beta forums or wait until the final release.
I remember that in my ZTE the exFAT was working, but you couldn´t grant write permission using the proper Android API, because the sdcard was not detected there. On the other hand that phone was rooted so I always kind of hacked around it.