How it works?
Start Global Settings and scroll down to section “SDCard and storages”. Android 5 gets new options “SD-Card permissions”. Under the title is button “Request permissions”.
This button calls standard android folder picker. In this picker switch to sdcard and pick folder where are your MS-DOS games and pick. After that your system allows to Magic Dosbox write access to this folder. This directory can be mounted like Drive C:\ now.
You can set access to whole sdcard, but this is strongly not recommended. It’s good to test this variant too, but please really backup your sdcard, or use another sdcard.
You should see picked path under the “Request permissions” button. If not, something is wrong – please report.
On earlier Android 5 versions happened that if the SDCard was without title then this picker caused crash. Title can be added during sdcard “format” phase. But this will delete whole sdcard, so beware.
After that, you will be able pick this special path in file manager. For example if you want set Drive C:\ in game profile. The special path is green colored.