LG C5 TV/Denon ARC/CEC issues

[KKTPA]

I have a Denon AVR hooked up to the HDMI 2 input on my LG tv. When I initially set it up, I was able to control the volume of the Denon receiver by using the LG remote. I enabled CEC Simplink and eARC on the TV and this allowed me to not only use the volume but also turn the receiver on and off automatically with the TV. Recently, my LG tv installed a software update and ever since that point, the TV reverts to TV Audio instead of HDMI 2 every time I turn the TV off and back on again. I then have to change the sound setting to HDMI and the volume control works perfectly. 

Any tips? I already tried unplugging everything including the HDMI cables, turning CEC and eARK off and back on again, and reverting to all original settings but nothing seems to work.

My Denon receiver does not have eARC support, not sure if that matters but I'd love to know the best way to set it up to control volume through one remote.

[benny blanco]

My parents are having a similar issue on their OLED (a 2025 model). Different Brand Receiver though (Yamaha). It was working for about 10 days off the AT&T set top box HDMI 2, eArc connection to eArc connection on a brand new Yamaha receiver off the AT&T remote around Christmas. Now, parents are struggling to use 3 remotes (at&t, LG, yamaha) to get audio and picture going on each bootup. 

Parent's have tried calling/working with LG Customer Support as the TV is still under warranty. Getting the run around are not Helpful. Best Buy hasn't been helpful yet either with Geek Squad either (where TV and receiver were purchased). AT&T says it's likely a TV issue, so they can't do much on their end.

[saha]

Made an account on this forum just to let you know you are not alone. My C3 was having issues with it staying on after my Apple TV turned off a week ago. And now a couple days ago my TV can no longer control my eARC soundbar. My TV is on the latest webOS so I assume the update broke it. Definitely a lot of issues going on with CEC eARC, but I haven’t found a good solution yet

[KKTPA]

Very frustrating. Clearly tied to a recent update for the TV as the problem started happening right after the update.

[saha]

So I ended up just turning off the breaker for my living room overnight. When I turned on my TV again, all the HDMI connections kind of reestablished themselves, and CEC was working perfectly again, I can control my soundbar now. Overnight and turning off the breaker is extreme, so maybe just turn off all power to devices and the TV for like 5+ minutes.

[benny blanco]

Update from my parents saga.

An LG CS rep came to the house and got things working again.. This lasted for a few weeks, and then the TV would just go a black screen after power up on HDMI 2 input where the eArc connection is to the Yamaha Receiver is.

Parents called up LG again and then were directed to call AT&T.
AT&T sends them a new cablebox (had to wait another few days for a tech to come out to install it) and now everything is working again.
Thing the source of all of this may have just been a super old/outdated AT&T set top box.

Will see if this finally fixes things.