So I have messed around with this for two nights now and it's driving me mad.

Samsung UE-55KS8000
Yamaha RX-V673
Harmony Ultimate

So I have the following set

1 Power on TV / Input Smathub and tried select no input
2 Power on AMP
* Input Smarthub
* Input AV1 (ARC back via HDMI from TV)
Delay
Command on TV Smarthub
Command on TV Right & Select (to take me to the netflix option)

Now all the logic seems correct but I think the AMP setting to AV2 is somehow triggering the TV back to the HDMI input on the TV, if that makes sense, so it ends up back on HDMI* with a grey screen waiting for an input.

How can i stop it trigger back to HDMI* on the TV waiting for an input

Thanks in advance!

Turn off HDMI-CEC, aka HDMI Control or Anynet in all your devices, and the odd switching will stop. Unfortunately this will likely turn off ARC as well. You may have to use optical for TV sound instead of HDMI in that case.

Cheers! That would explain the issues I was having last night then, I tried that but kept dropping the sound... Time to dig out the optical cable ....

I'll reply back with the outcome!