The only reason when these issues appear is that you dont mount storage with full write access. Bug is that kitkat reports read-only disk like a write-able. Will try fix it. However it will not work until you dont grant full permissions. You use legacy rom, this is custom rom right? maybe is broken. 2-3 years ago was mdosbox tested on multiple games and worked, i dont know on which android version it was, maybe i can find it on web. If necessary I can share for a test that old version, however you can do the same test with afreebox, free version of dosbox turbo