Hex Editor with SNES HiRom

[madsiur]

In the case anyone knows how to do that?

You could check FF3SE source (here) written in C++ or my editor source (here) written in C#. This could give you an idea on how to open ROMs and check how data or graphics are managed.

There are other utilities sources available online such as FF6LE, Zone Doctor. I find these two having a better code structure than my editor. You can open any C# solution with the (now free) Visual Studio.