Yamaha receiver won't output video to UHD television

[hasse.hassedorm.dorm]

I have attempted to connect a Yamaha RX-V481D receiver to a new LG 4K/UHD television (55UK6100), which displays "no signal" when connected to any of the television's HDMI input ports.

I have tried the following:

Change "4K mode" in advanced settings to either mode 1/2
Four different old and newly bought HDMI cables
Factory reset of the receiver
Firmware update of the receiver (current v2.58)
Firmware update of the television
Confirmed that the receiver worked well on an older LG television which did not support 4K.
The television accepts either of appliance directly to the television, but not via the receiver. The television "reacts" when the receiver's HDMI cable is connected, and displays the "no signal" shortly after.
The television is able to show 4K resolution directly, from a laptop, while the receiver fails any resolution.

The media sources into the receiver are either Chromecast, a new-ish laptop or a classic cable set-top box. This means that the input signals are not 4K, rather 1080. There is no video from the receiver on its own either, such as the Yamaha settings menu, which shows up when no input is connected to the receiver.

My attempts are made of what I could gather of tips online. Am I missing something obvious?

 

[Lutfij]

Considering your receiver is the mediator between the media(source) and the television, I'm curious enough to ask what the source of your content is?

 

[hasse.hassedorm.dorm]

Considering your receiver is the mediator between the media(source) and the television, I'm curious enough to ask what the source of your content is?

Thanks, I've updated the question

 

[americanaudiophile]

Try selecting the HDMI input on the TV after the receiver has fully turned on and the source is active. Maybe it will handshake then.

 

[hasse.hassedorm.dorm]

Try selecting the HDMI input on the TV after the receiver has fully turned on and the source is active. Maybe it will handshake then.

Thanks for your suggestion. Sadly, I've tried to no avail. It seems to me that the TV "reacts" to the HDMI connection as the message "HDMI X is now available" appears (with no signal). I figure every new linking of two devices by HDMI triggers such a handshake?