The overworld border is pretty limited to edit, especially because it's a fixed tilemap in comparison to e.g. the status bar, especially the super version. Because of that, I made this patch which enables you to edit at least the top and bottom part.
For a list with (in)compatible patches and codes and, check out this thread.
As always, the readme contains more information.
Request made by GreenHammerBro.
Tried to insert, and...?
This happens in a loROM;
The level names disappear in a SA1 ROM.
Last but not least: is there some other step I'm not aware of when inserting the patch? Because if there is, please specify in the readme.