I've read that there is no OTG support and see no reason why this is the case. I have a couple of DAC's and they have worked on all my android devices (SINCE 4.4). It is not a hardware limitation. If you get CM (dead now, but you know what I mean) on any device using android 4.4 onwards it will work (at least mines work).
I honestly did not expect it not to work on my Nextbit Robin. Bought one and that is the only thing I can not do on it (grrr). I really can not stand BT or any sound output from normal headphone sockets.
Please please please, just enable it. Don't care about OTG storage or anything like that. I just want to hear good sound quality out of my phone.