I’ll be honest and say it seems I have made an oversight with HDMI cable selection.
During the ‘evaluation’ phase for peripherals I measured the quality of the cable but did indeed omit checking CEC compatibility.
My focus (trying around 10 different manufacturers) was to see which one had the best shielding and least noise across the cable, but it seems like CEC is problematic with these, and for that I do apologise! Even more oddly: price does not seem correlated to cable construction quality at all. You can get one for $5 or even bundled with a PS3 that is better than the ‘premium’ aftermarket cables that can run up in to the $70 range…
Nonetheless, CEC was not working until this update, but it would’ve sure saved us some time had we known this in advance.
S