1) So far, these buttons never worked, I will test again this evening. However, I doubt they ever will, because the 2500BT has a different interface: first one has to open the on-screen menu for audio, then one can select an audio track. The same with the subtitles.

2) No it doesn't with the default delays, I still got lock-ups. Now I use 300 general delay and 400 poll delay and that works without problems, except that sometimes I still get the error message above, but without apparent reason, because the module at that moment has done and still does all it should and doesn't lock up.

In this context I should maybe mention that my RFX9600 isn't directly connected to the router via ethernet but via a WLAN bridge, which probably causes delays(?).

3) I really like your homescreen for the 9600. In fact I have made one for the 9400 and for my devices that looks quite similar!