Jnardone_PDX +1 for me as the 4K FireTV stick has been working great over CEC with my 8x8, and I have the same occasional problem with it locking up and needing to be rebooted. Searching the internet, it looks like FireTV's are known to occasionally stop responding over CEC for some reason. I wasn't sold on it being a FireTV issue thinking it might be a Crestron issue but I wound up? confirming its the FireTV by waiting until mine locked up and then moving the HDMI cable over to a 2nd FireTV and Crestron controlled the other unit just fine, which proved it was the FireTV.
