The entertainment mode does disable some audio and picture settings. That was the design of the mode, and it's highly unlikely that it will be addressed with a firmware.
The right and left audio outs have an amp that runs to the receiver. The output is designed to pass the signal enough for an external amplifier to amplify the sound. It wasn't necessarily designed to be used with a subwoofer; however, since it has its own amplifier, I salute your ingenuity of using it as such. (It will not damage the output, in case that brought up the question).
And you're welcome.
I get surprisingly good sound using the sets custom equalizer and an external sub woofer. However, if I use the 'entertainment mode' on the remote to select any other mode than 'off' the sound is terrible. Each selection - sports, movie, game is different tonally but they are all awful- tinny, flat and muffled. In all the E. modes but 'off' the equalizer is locked out therefore I can't adjust the tonally quality of the sound. If this is normal then we need a software update to allow a custom eq setting in each e.mode. Also it would be nice if the right and left audio out adjusted with the sets volume control. I have my subwoofer plugged into the right channel and have to manually adjust it for each show.
Thanks again for being so attentive to all the forum users questions.