It may just work by luck, as this screens are not supported by the standard, same problem in Retropie. You can find the documentation here :
Now, you can always try out some things. For ES, it should be in /recalbox/share/system/recalbox.conf the line : global.videomode=default or to find a working way around with offsets. Not sure that it will work.
What else could help you, the descriptions in this config.txt