I’m sure Sam will correct me if I got something wrong here but I believe what you would need to do via ssh…
sudo cp /sys/class/amhdmitx/amhdmitx0/disp_cap /home/osmc/.kodi/userdata/disp_cap
sudo chmod 755 ~/.kodi/userdata/disp_cap && sudo chown osmc:osmc ~/.kodi/userdata/disp_cap
nano /home/osmc/.kodi/userdata/disp_cap
add the missing options, save and exit nano (ctrl+x, y, enter), then reboot.
I’ll give this a try in the morning–maybe Sam will chime in by then.
Do I hit enter after the first line? I need exact stuff to input. I’ve got Putty connected to the Vero via ssh, but that certainly doesn’t mean I know what I’m doing. 
Thanks again everyone for your help. I’m gonna leave it alone until tomorrow, because I’m going to be watching it tonight!
Those are the correct instructions indeed.
You hit enter after the first line and it will copy your current settings to a file that Kodi will read instead of getting the info from your TV. The second line will open that new file in a text editor and you will see a list of supported resolutions and frame rates and it should be pretty obvious how the ones you want added should look. You will navigate with the arrow keys on your keyboard. It shouldn’t be too hard to figure out. Otherwise you could google “how to use nano” and that will lead you to much more information than what you need for this simple edit.
Good morning.
I’m getting this: [ Error writing /home/osmc/.kodi/userdata/disp_cap: Permission denied ]
In fact, it warns me that the file is unwritable when I open it using the instructions above.
I think we’re close.
Sorry about that. I edited that post with an additional command to give ownership and write permissions so you can edit it. If you run…
sudo chmod 755 ~/.kodi/userdata/disp_cap && sudo chown osmc:osmc ~/.kodi/userdata/disp_cap
you will be able to save it without that error.
Brilliant! It’s working as it should now. Thanks again for the help!
Is it odd that the TCL Roku TV doesn’t report all the refresh rates it supports?
At any rate, I’m well pleased. Once again, the Vero proves itself able to play anything I throw at it (as long as the TV doesn’t sabotage anything).
Thank you so much for providing this help, it worked for me greatly.
With the most recent October 2022 update though, it actually borked my Vero when I updated to it and I had to SSH into it and kill all my userdata to get it to be accessible again. So for people who have used this fix, I would recommend switching to a lower/more standard within OSMC resolution/refresh rate combination before applying the update. Maybe it will help and then you can switch it back on the other side.
I was able to get things working by starting from scratch and re-applying your fix, but it took more time.
Cheers!
Did you try to remove just disp_cap and restart mediacenter before removing all userdata to see if this is really the issue you ran into? I’m not aware of any changes in this regard so perhaps @sam_nazarko can chime in with some insight.
Nope, I am not sophisticated enough to do that. But it did bork again on a reboot when I changed some graphics setting in the UI and now I have to start from scratch again, so it seems like something with the October update and my settings. Black screen on all my monitors.
When your in the black screen phase if you SSH into your Vero and grab-logs -A that will give you a URL to your logs that you can post in this thread. That may help the devs to spot what is going on. As for isolating if it is that file causing it…
systemctl stop mediacenter
mv ~/.kodi/userdata/disp_cap ~/.kodi/userdata/disp_cap.old
systemctl start mediacenter