Android 6] USB drive access issue

HI,

I have encountered a new issue using games collection on USB drive :

This USB drive is well detected (all files and game collection) on my Android TV box (based on Android 5) : no issue with Retrox.But now, I have just installed Retrox on my smartphone under Android 6, and using this same USB drive (with OTG cable) => no detection.(and there is no file manager as ES Explorer installed)In fact, the system on my smartphone detects correctly this USB drive but only with the official file explorer (browsing is possible) and in Android system storage menu (local, external).But impossible with other app. It seems Android 6 manage the external USB storage differently than previous version. Is there a solution?(and I have no more free space on local storage to move some games into)Is there a technical way to adapt the RetroX app or not?Thank you for your support.

Thanks

I did not find the right solution from the internet. References:

http://forums.retrox.tv/viewtopic.phpt=295

Animated Explainer Video

thanks!

Are you writing about banana-pi-r2?