Mini DP - HDMI i5 Mac Mini SwitchResX 4K Start Up Issues. Anyone else see this?

15 replies

I'm working on getting an i5 Mac mini to display to an LG 4K tv for a studio we're building at the office. I bought a Club 3D mini DP to HDMI adapter and downloaded/bought SwitchResX to unlock and utilize the higher resolutions and refresh rates. I can get the highest resolution and frame rate combination to work through SwitchResX, but as soon as I reboot the Mac Mini, after the Apple logo loading bar screen passes, the screen flickers and flashes green. I then have to unplug the HDMI cable from the adapter and plug it directly into the Mac Mini which then displays the Mac's desktop. I can then plug it back into the adapter to take advantage of the SwitchResX resolution for 4K. I've scoured different forums to no avail. Has anyone seen anything similar? Any help is appreciated.

Hi jefftv

What build year is the Mac MIni ?
Which OS version do you have installed?

You have "UHD Color" en-abled in the menu of the TV ?
(or something like "PC-Mode" or "Game-Mode")

I just set it to "Game." Should I try a reboot to see if the flickering goes away?

Just tested under game mode and still flickering. I also tried under HDR mode set to high and I also set HDMI Ultra HD Deep Color to on for the port I'm using.

Any more ideas? None of the recommended actions have changed the outcome.

HDR mode is not supported.

Only think I can think of is the Pixel Clock,
Please check in the SwitchResX setting what frequency the Pixel Clock is at.

Please note that it depends on the screen if the what pixel clock is supported,  however often automatically is set between 533 and 539MHz.

I tried this and it made it so that it always flashed green whenever I plugged in the tv through the adapter. Once I deleted the custom resolution configuration and rebooted, the green flashing only happens on start up. I can then switch to the HDMI port and then switch back and I don't get the green flash after boot up.

Hi jefftv,
It sounds like the system does not recognise the screen and chooses to send out a signal the screen does not "like" at boot up. After you change settings all is fine, until next boot.
Normally an app like SwitchResX would solve that becuase it overwrites the normal system setting and "forces" the sytem to output whatever you want. That his does not function after boot, it a new one for me.
What firmware is on the adapter (should be mentioned on the label on the cable).?

Hi jefftv,

You already have the latest available firmware, so from the adapters standpoint it should all be good and working.
Sorry for the inconvenience,

Could it be that there are other pixel clock settings that could help here? I suspect that the settings above may not be appropriate for my specific display.

Is there a place where I can check to see what my specific model TV pixel clock settings should be? I own an LG 43UJ6300 4K LED TV.

Hi jefftv,
That is most certainly possible, but if anyone should know it would be LG ... i have no access to such info unfortunately. If you are lukcy it is mentioned in the manual, but often you would have to contact the Manufacturer.

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