Just to share my testing results of trying to get global write/delete permissions for Kodi on all external storage, besides the allowed folders ../Android/.data/org.xbmc.kodi on SD and HHD. So I decompiled the latest Kodi APK and added <uses-permission android:name="android.permission.WRITE_MEDIA_STORAGE"/> to the androidmanifest.xml file. Re-compiled and signed the apk again. Unfortunately as many thought android.permission.WRITE_MEDIA_STORAGE is not an official permission settings that can be used for store apps but is reserved for Android system apps only. So, I temperately rooted my device and moved my Kodi version to the /system/app folder, which augmented its permissions and this action allowed writing and deleting anywhere on the external storage's. But I don't like this. I did a lot of research and the only way I found to have full write permissions is by adding this line <item name="android.permission.WRITE_MEDIA_STORAGE" granted="true" flags="0" /> to the \data\system\packages.xml file. This can be done for all apps that you would like, like Es File explorer, Titanium backup, ... The only other option I found to achieve the above tweak is to root your hub, install Xposed Framework; Xposed Installer and the Marshmallow SD Fix app from the Google store. There are a lot of tools out there change will try to change the platform.xml, but this is not working for me. It freezes my hub. Perhaps putting in directly into the Minix firmware could work. So to conclude, not possible in my opinion if you are not rooted. So not really worth it?