Monday, 26 January 2015

Taito G-Net Mod BIOS

Some kind chap over at Neo-Arcadia has taken the trouble to dump the 2009 Mod BIOS and share. ^_^


G-Net Motherboard
PCMCIA Compact Flash Adapter
Compact Flash card
Windows PC capable of writing to the Compact Flash card
1 x Blank 27C800 EPROM
EPROM burner compatible with 27C800 EPROMs
G-Net Mod BIOS
G-Net Flashing software (this is to put the games on to the CF card)
G-Net CHDs  (after downloading rename the zips to chd)

Update the G-Net BIOS.

Download this BIOS file and burn to an blank M27C800

Remove any PCMCIA cards from the G-Net system
Bridge Jumper JP1
Insert the M27C800
Power Up

There will be three progress bars across the screen and then a message in Japanese telling you the flash is complete. Power off the system and remove the jumper. The system has now been updated.

Putting the games on the cards.

Download and extract the G-Net Flashing software and the chd pack

Open up the flasher, select the chd file and write it to the card. Once complete insert in to the G-Net and power up.

Non Windows users should use chdman to extract the image file from the chd. (You may need to compile/build this from the MAME surce code) 
chdman usage;
chdman -extract game.chd game.img
Once extracted write the game.img image to the CF card using the dd command or and image writer

If you get 000001 SYSTEM ERROR It is likely that the CF card you are using is not adequate. Sandisk (64MB - 2GB are preferred) If the message 000777 SYSTEM ERROR is displayed then the mod BIOS hadn't been correctly flashed.

If anything goes wrong or you want to return to stock flash the original V2.0 BIOS. This and the flashing guide can be found here.

Thanks to aje_fr at the Neo-Arcadia forums for dumping the BIOS.


Here is a link to the 2011 version if the netload link dies. Thanks. :)

G-Net Mod BIOS - 2011 version 


  1. Too bad its not based on the newer modBIOS... It supposedly supports more CF brands..

  2. Thanks, I've tried this with quite a few different Sandisk CF cards and they have all worked, Trancend Industrial also worked. The Chinese fake Sankdisk from ebay didn't work.

  3. Thanks but the chd links are not working right now.

    "Not Found

    The requested document was not found on this server. "

    1. Cheers, now fixed. Sort of... You can now download the files but will have to rename them once downloaded.

      It's strange that the server I use will not serve chd files. The fact that you could see them means they're present as it's a simple directory listing.

  4. Hi
    Do you sell this pic m27c800 already burned I don't have a EPROMs burner .

    1. I can probably burn you one, where are you located?

    2. I leave in Spain If you can send to Spain .i pay you whit PayPal .

    3. @ikotsu
      Would you have a burned ROM available for sale? I'm in the USA.

      Thank you.

  5. This comment has been removed by the author.

  6. There is a newer BIOS file at neo-arcadia. Is it a newer version?


  8. Cool all we need is all the roms somewhere now


  9. Hi'
    I don't know who post the MB-2011 version, but I'm also the author of it.
    It's my file ;-) and was a private one shared to only few friends and it should be released within few weeks.

    1. Thanks for making it public

  10. The flasher software is detected as malicious by Avast, not sure if that's a false positive. Image extraction/writing with chdman/dd works fine though.

    Transcend TS4GCF133 cards work fine with the mb2011 version. Thanks for sharing.

  11. The Flashin Software does not start on Windows 10 Computer, what can I do"

    1. Try Win32 Disk Imager:

  12. hello,
    is it possible to buy a gnet modbios from you?

    Thank you in advance