I've got a UN49KU6400 TV, and a HT-F5505k Home Theater, both from samy.
They are conected through the ARC enabled HDMI input and everthyng works fine, excpet a very annoying issue that everytime I turn the TV on, it turns on the HT, and switches the input to the HT HDMI. This happens when I switched off the TV on the antena source.
If I switch off the TV on the PS4 source (HDMI 1), when switch the TV back on, it will switch HT on and output the sound on the HT, as expected, and will not switch the source, but normally the TV is turned off when watching TV (antena).
Recently, I noticed that this behaviour doesn't occur when I turn on the TV from the power button on the unit. It's seems turning on has different process on the unit power button from the remote control. When I turn on from the unit button, the TV displays the "Smart TV" logo, while turnint it on from the remote control, it doesn't. Weird!
The firmwhere is up to date (v. 1220.6). It uses the same firmware from the KU7000...