I've done the about:config thing in Android KitKat to set browser.download.dir to micro SD storage. Had to create an Android/data/org.mozilla.firefox/files/Download folder on the micro SD b/c FireFox is not given permission to write anywhere else by KitKat. All of that works great, except: I can only save .text and .zip/.far files to the micro SD card. Whenever I try to download an .mp4/.mkv file, a dialogue box opens asking me whether I want to use FireFox download or an installed media player to open the file. This happens while I'm surfing thru FireFox BTW. And if I select "use Firefox download to open the file", it gets saved on my internal storage not on the micro SD card. How do I rectify this problem?