You'll find that this community is still relatively small, imo. Some posts can go longer than 3 days without a response. Please keep duplicate questions to a minimum.
That being said I've only tinkered with RetroOrangePi a couple times so I'm not gunna be the one to help you. The very (and I mean very) little knowledge I have tells me editing boot.cmd would be easiest. Don't quote me.
I do remember having resolution issues on a 720p TV (Opi PC+) though and this thread helped me customize the settings for a fix. Good luck.
