SXROM 32KB Emulator Issue [Solved]

[nesmaster14]

I've noticed an issue on the Famicom game Dezaemon. Whenever you go to save an edited file, the save is lost or was never written. I've tested the Dezaemon ROM on a few emulators as well as on an Everdrive N8. The game runs, but its most vital feature (saving) does not work. Any idea why this happens? I read somewhere that SXROM games need to be in the NES 2.0 format to be read properly on emulation (otherwise they'll be read as a lesser sized SUROM/SNROM)? My theory is the .nes file (?) needs to be updated for the NES 2.0 format, so the full 32KB SRAM bank will be saved, but I have no idea how to do so. Any info/help is greatly appreciated! I feel this game would benefit greatly from having emulation/flash cart support due to the save-oriented nature of the game.

Also, I own an original copy of the game if anyone wants a scan of the PCB. Additionally, if you need info on how to navigate Dezaemon, I know my way around.

Thanks

[koitsu]

You can update the header to NES 2.0, but there's no guarantee the emulator or device you're using supports the 2.0 bytes. You're looking at byte 10 of the header:

Format: http://wiki.nesdev.com/w/index.php/NES_2.0

[lidnariq]

Dezaemon's SXROM would be specifically these 16 bytes:

Code: Select all

4e 45 53 1a 08 00 12 08  00 00 90 07 00 00 00 00
            |/ |/ ||  |        |   |
  128 KiB PRG  |  || NES 2.0   |   8 KiB not-backed CHR RAM
      no CHR ROM  ||    32 KiB battery-backed PRG RAM
               MMC1|
                   Battery

Easiest is to load the ROM in Nintendulator's header editor.


Edited to incorporate Joe's correction. I naïvely assumed all SXROM games were 512 KiB PRG.

[Joe]

I think Dezaemon has only 128KiB of PRG-ROM:

Code: Select all

4E 45 53 1A 08 00 12 08  00 00 90 07 00 00 00 00
            |/
  128 KiB PRG

[nesmaster14]

Alright, I updated the header and it seems to be working now! Thanks for the help guys!