4K TV issues, new install on N2

Hi all
Having an issue with a newly delivered N2 - trying to get Coreelec working which is doing some sorts of weird things…
I have a 4K TV down in the kids’ room which is what the N2 was meant to be for - I go the Coreelec 4GB edition and also a 32GB eMMC with Android for playing around with.
Could get Android to boot from the eMMC, but was not able to get Coreelec to boot at all - it would go to a ‘no signal’ screen, then blank for a few seconds, then back to ‘no signal’ screen.
I connected it up to the 1080p screen in the other lounge and it finally managed to load, do the expansion of the partitions, although it was throwing various errors saying it couldn’t do various things, and saying to type exit to continue which I dutifully did.
Eventually I did manage to get it to load Coreelec on the 1080p TV, but taking it back to the 4K TV after that was the same as previous - not loading, although did get a blank screen briefly. So it seems as there is some issue with the HDMI output not syncing with the TV at 4K.
Any ideas on how to proceed from here? Is there any way I can set the resolution pre-boot so that it will show something on the screen?
Thanks for your help

Maybe have a read link below in case it is your problem.
No resolution available higher than 1080!.

I’m no expert but I had issues with N2 and 4K too.
You can try the next:

  1. Set the CE gui to 1080 and see if the 4K TV is able to see CE boot.
  2. Make sure your AVR’s HDMI signal is set to Enhanced and not Standard.
  3. Make sure you use an HDMI High Speed 18gbps cable. AmazonBasics and certified Monoprice cables usually work for most people and are cheap.
  4. Try different HDMI ports on TV.
  5. Try to set Chroma Subsampling on System --> CE to 4:2:2 (requires reboot).

If non of those work, you may be one of the unlucky ones (like me) with a likely damaged HDMI port on the N2. In which case be sure to RMA it quickly, unless you bought it with an extended warranty or from a European vendor. Standard warranty from almost anyone else is only 4 weeks.

Thanks for your input guys.
Weirdly, after lots of reboots and passing through a series of errors from the N2 saying it couldn’t find various bits of the OS, it booted!
I was fairly happy that things were working reasonably well as far as HDMI ports go, as it would boot into petitboot and I got Android working also. Still really unclear what it’s issue was that prevented it from booting Coreeelc and no idea if it will boot next time given all the file system errors I was getting, but happy now that I have managed to get it set up and loading all the different addons and the libraries onto it.
Will come back to the thread if the same weirdness happens again, but hopefully that is behind me now!