For the resolution “issue”, it’s actually normal, apparently the OSSC displays the number of lines rather than the resolution. Someone taught me that a few days ago, I don’t really understand why but that’s how it is. Anyway, this is normal.
As for your main issue, I just have a couple of advice :
-share the specs of your TV, brand, series, resolutions etc, it might be helpful for people who want to understand your issue.
-try to activate the “PC” mode, maybe your tv will accept more “strange resolutions”
-try another HDMI cable (we never know)
-can you try on another tv ? So we can rule out the OSSC as the source of the issue
Also, have you tried 240p games in 3x, 4x and 5x mode as well ? Your tv doesn’t accept any of those ? Try to test all the possible configurations and with as much consoles as you can.
I know I’m not very useful here, but unless people have a ready-to-go solution for you, they’ll probably going to need those answers, might as well give them as many tools as you can now so they help you quickly and effectively.