Top is the info.txt from the latest HW-N950, bottom is the text from the eARC update of HW-Q90r.
As you can see it's just generic Tizen. The hardware in both sound bards is basically identical, and whatever differences there are, shouldn't influence eARC which is basically a software feature.
Things get even more interesting when we open the HW-Q90r firmware file with a HEX editor. The HW-N950 (SAT-HKA18WWC) is literally mentioned in the file headers.
I see this as a huge f*ck you from Samsung. There was an implicit promise that the HW-N950 would get eARC, and seeing how it seems to be literally baked in the firmware (it's just a Tizen distro with software features after all), it feels wrong doubly so.
Are we getting this update or not?
I take the previous mail was an official response from Samsung. How pathetic. 
Instead of relying on Samsung to improve, much less hassles to just buy another brand’s model. Other than the EARC (the lack of) feature, the N950 has issues like 1. Rear speaker distortion noise, very sensitive to certain WiFi channels, and its not adjustable. 2. Low rear speaker volume for music surround sound use, 3, massive lip sync delay when working with Netflix, sync feature will not help; 4, random popping sounds from the sub woofer. Overall, it’s just a half baked product. I see why Samsung has given up supporting it. So just move on, get a Sonos instead 
I was trying to decide which 49 inch computer monitor I should choose between Samsung and LG, even tho LG one is more expensive, I went for LG because of this frustrating Samsung sound bar experience. I am now a happy LG customer
