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Unable to get Modbios games to boot

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Tonybolony

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So i did the Modbios with the 2011 version as people say, it all flashed good , but i can get any game to boot past the logo screen , they Just go system error 000001 , my original game works

could it be the CF card ? , any help appreciated
 
Tonybolony said:
So i did the Modbios with the 2011 version as people say, it all flashed good , but i can get any game to boot past the logo screen , they Just go system error 000001 , my original game works

could it be the CF card ? , any help appreciated
Click to expand...
Usually the card. Try another brand if you can.
 
I'm having similar issues.
- I replaced the chip with one with the new bios
- put the jumper on JP1
- got the standard set of CHD roms online, converted them to .img with CHDman and flashed the SD cards with Rufus. This is what the content of the SD card looks like for Night Raid

Didn't work - got a progression screen that stops, no matter what game I use (I'm using Sandisk cards)

Then I took out the jumper

Also didn't work - got the GNet logo, then a screen saying 'system error'. Note that if I use an original GNet card this set up (mod chip, no jumper) works.

Any clue?

Not sure if I'm not converting the rom properly or there is some other issue
 

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use HDD Raw Copy Tool not Rufus , also look online there is a pack of the Gnet roms already converted if i remember correctly
 
tried HDD Raw Copy - no difference (the content of the card looks the same FWIW).
Keeping the jumper on JP1 I get 1F100000 ERASE ERROR
Taking the jumper out I get 'system error' right after the GNet logo shows up
 
i had issues and i used jessop CF cards and they worked , my advice get the Gnet roms that are already converted
 
thanks. I got the raw file, flashed to the CF card with HDD Raw tool. no change. still get the 1F100000 ERASE ERROR with the jumper on, 'system error' right after the GNet with the jumper off.
Is it possible I mounted the chip upside down or it doesn't really matter?
 
With the jumper on, it sounds like it's having trouble erasing the flash chip for the BIOS so it can write the modded BIOS from the EPROM. Without the mod BIOS in place, non-official CF cards will boot.

The orientation of the EPROM does matter. There is a notch on one end of the EPROM that should match the notch on the socket. Do you have it oriented correctly?
 
I checked the notch and it was already oriented correctly.
FWIW, without the jumper, official GNEt cards work with the modded EPROM in

Are you suggesting I put the original EPROM in? Jumper in or out? Or any idea on how to fix this? Thanks so much in advance
 
The GNET board stores the BIOS on a flash chip. The jumper is typically only used when flashing the board’s flash with a new BIOS from the EPROM. Once the new BIOS has been successfully flashed once from the EPROM, you won’t need to use the jumper again-or even the EPROM for that matter. The socket can be left empty.

In your situation, the error indicates that it’s trying to relflash the BIOS from the EPROM but it’s having trouble. The culprit is either the EPROM or the flash chip on the board itself that stores the BIOS.

You should verify that the EPROM is functioning and has the modded BIOS written to it correctly using an EPROM programmer. If you’re sure the EPROM is correct then the flash chip on the GNET board itself should be desoldered and replaced.
 
Very insightful. my Gnet board works and can load original cards. Can I assume that the flash chip works or even if the board loads original cards the flash chip could be compromised?
 
The factory Taito BIOS is still intact which is why your original GNet carts still run. The issue is that the flash isn’t erasing the factory BIOS so that the modded BIOS can load in from the EPROM.

What EPROM are you using for the mod BIOS? It should be a 27C800.
 
Not sure. I bought it from this dude on eBay
 

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I don’t know who that seller is so I can’t vouch for the EPROM you bought.

If you like, I can make you another mod BIOS EPROM for $3 plus shipping. I’ll test it on my G-Net before sending it to you.

Or if you prefer, you could send your G-Net board to me and I could replace the flash chip on the G-Net PCB if it’s necessary. I know how to SMD solder and I have a long track record of arcade board repairs.
 
Not one of mine (eproms), I use typically use plain labeling and don't recreate logos. Someone just bought one from me, so thanks if that was someone here :)
 
ShootTheCore said:
I don’t know who that seller is so I can’t vouch for the EPROM you bought.

If you like, I can make you another mod BIOS EPROM for $3 plus shipping. I’ll test it on my G-Net before sending it to you.

Or if you prefer, you could send your G-Net board to me and I could replace the flash chip on the G-Net PCB if it’s necessary. I know how to SMD solder and I have a long track record of arcade board repairs.
Click to expand...
Awesome! I sent you a private message.
 
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