On LG TVs running WebOS 4.0 with software version 05.10.25 (released November 2019), CEC does not function on HDMI 2 — the port labelled ARC. This is a known firmware issue specific to that LG software release and is not caused by the NUC-CEC adapter or libcec.
Symptom
CEC commands from your NUC are not received by the TV when the NUC is connected to the HDMI 2 (ARC) port. Other HDMI ports on the same TV may work correctly. The issue only affects this specific LG firmware version.
Fix
Connect your NUC to HDMI 1 instead of HDMI 2. CEC communication will function correctly on HDMI 1 on this firmware version.
1
Power off the NUC and TV. Disconnect the HDMI cable from the HDMI 2 (ARC) port on the back of the TV.2
Connect to HDMI 1. Plug the HDMI cable from your NUC (or NUC-CEC adapter) into the HDMI 1 port on the TV.3
Power on and test. Boot the NUC and confirm CEC commands are working — for example, verify the TV turns on and off via CEC Tray or cec-client.If you update your LG TV's firmware to a version newer than 05.10.25, check whether HDMI 2 CEC functionality has been restored. You may be able to move back to HDMI 2 after a firmware update.
Affected Configuration
This issue affects LG TVs with all of the following:
- Operating system: WebOS 4.0
- Software version: 05.10.25 (released November 2019)
- Port affected: HDMI 2 (labelled ARC)
Related Articles
- Intel NUC CEC Adapters — Hardware Compatibility and Legacy Notice
- Getting Started with the USB-CEC Adapter
- How to Install libCEC (Windows)
Still not working after switching to HDMI 1?
Contact Pulse-Eight support with your LG TV model number and software version.
UK: 01202 413 610 | US: (858) 748-8250 | support@pulse-eight.com
Contact Pulse-Eight support with your LG TV model number and software version.
UK: 01202 413 610 | US: (858) 748-8250 | support@pulse-eight.com