Contra (U) with a single byte changed, making the game crash (probably a hack for idle loop detection).

There wasn't anything particularly interesting in the four ROMs I looked at: On top of that, some of these ROMs have been hacked specifically for the emulator. It looks like you can take the two-byte (big-endian) value at offset 6 and add $61C0 to get the offset where the ROM starts, but there's no clear indication of ROM size, mirroring, or mapper. I really want to play some games which I cannot find on the internet. Can anyone solve the puzzle? I can send some of the rom files and I also have the name of those games so that you can compare to a fresh rom. This topic has been discussed on many places but I did not find any solution anywhere.

I'm not a NES developer and I don't know how to modify or fix a NES file, so I may be wrong.

Those bin files has fresh rom data without NES header and some data added before and after the rom data. bin files with original NES roms in a hex editor. The CD runs on thos VCD player but not on any emulator on PC. This CD comes with some old VCD player with game facility. bin files which are some kind of processed NES roms. It's a CD as like as video cd structure (with CDI, EXT, MPEGAV, SEGMENT, VCD folders ) with an extra NEWROM folder. There isn't a single clue if anyone was able to rune these games. Searching over the internet since a few years. I'm trying to run these games for a long time.

Super game vcd 300 nes rom