To run the VELF emulator at least the VELF system ROM file should be specified in the 'ROM' field. Default VELF ROM location is the Velf directory (located in the application data directory, see Directory and File Structure) and the default filename is 'VELFbios-v3.1.bin'. To change the location use the 'ROM' button to browse for the file, do the same to change the filename or type in a new file name in the text field.
The binary, Intel hex and RCS Elf Emulator hex format are supported.