@obero
for movies and videos I use MX Player
for music I use Poweramp, but MX Player can play music as well.
@dan0412
for me it works on the unactivated version of Emteria. I have few more things to test before buying the licence.
ES Explorer saw my USB drive from the begining. Only the music player didn't. After the command I mentionned earlier, the music player can see my USB drive as well.
My USB drive was formated in FAT32 and I gave ES Explorer root rights.