No signal when putting interface in 4k

[boot2k3]

You can try this solution in additional to cable

9.0.1 Discussion

@suhanbongo some LG displays are problematic, enable the following option Settings>System>CoreELEC>Use 4:2:2 colour subsampling Revert the whitelist changes you made and you should be okay then, GUI should also be at 1080p for HDR autoswitching to work correctly.