roku-like audiocast to phone / headphones
I found a rather dirty hack that seems to work better than Bluetooth audio for listening to private audio from the firetv.
Installing bubbleupnp works good on my phone for audio casting to xbmc, so I tried the same on the firetv in reverse.
I had the xposed installer already on the firetv for llama support, so all I needed was to install the bubbleupnp app and bubbleupnp module in xposed.
Experimenting, I played from xbmc to my bubbleupnp app on my phone and it worked. There was a little delay, but it was more constant than the delay that BT headphones have with the firetv. Adjusting the delay on the xbmc app, and I had my private audio. I hadn't tried with any of the other video apps on the firetv, but I'm thinking the delay will be there. At least I can use it for xbmc.
Just wanted to put that out there. Hopefully a better option for sending and listening to audio will come out soon.