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PostPosted: Mon Jan 28, 2019 10:03 pm 
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Hi all,

This is my first post, so I’m sorry if it’s not in the right spot.

I’m new to repro soldering boards (have used flash boards) and I’m trying ReproX. I’m trying to put a translated BNROM game on an AM27C020 with CHR-RAM. I was told that I do not need to split the game because it uses CHR-RAM instead of ROM. I checked the how to guide which does not help with this. How should I write the game to the eprom if I’m not supposed to split it? Thanks in advance for any help!


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PostPosted: Mon Jan 28, 2019 10:07 pm 
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For games that use PRG ROM and CHR RAM, you chop off the first 16 bytes (the header), and what's left is the PRG ROM. You write this entire file to the EPROM.

Consider, for example, the Haunted: Halloween '85 demo. It's a 1 Mbit BNROM. Offset $000000-$00000F is the header, and offset $000010-$02000F is the PRG ROM. You'd write that to the EPROM, set the jumpers for BNROM (vertical mirroring, 32K PRG banking, no CHR banking), and ground the EPROM's A17 because only A16-A0 are needed for 1 Mbit.

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PostPosted: Mon Jan 28, 2019 10:08 pm 
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You still need to remove the header from the .NES file. It's just the first 16 bytes.

But... just use whatever the NES splitter program is. It should do that for you, you just get one ROM instead of two.


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PostPosted: Tue Jan 29, 2019 4:18 am 
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Thanks so much to the both of you. I'll give it a try today.


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PostPosted: Tue Jan 29, 2019 7:03 am 
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So I'm a little confused. I most familiar with Famirom for splitting, but there is no option that I can see to remove the header. The game I am trying to put on the eprom is Dragon Ball - Shen Long no Nazu translated into English. Is there a program that is best for removing the header from NES ROMS?


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PostPosted: Tue Jan 29, 2019 7:54 am 
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I tried using NES Mapper Reader / Rom Fixer / Rom Splitter and I checked off to remove the header and auto split the PRG and CHR. I get 3 .bin files. The "unheadered" version is the same size (161 kb) as the original .nes file. I tried using the created file on my eprom and I get a black screen.


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PostPosted: Tue Jan 29, 2019 8:32 am 
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Three observations:

  1. Practically all physical ROMs are a power of two in size, such as 131072 bytes (128 KiB, 2^17 bytes) or 262144 bytes (256 KiB, 2^18 bytes). In-between sizes, such as those of Action 52's PRG ROM and many Super NES games, are the result of having two or more ROM chips on the board. A 160 KiB ROM, for example, is usually 128 KiB + 32 KiB.
  2. Bandai's Dragon Power is not BNROM but GNROM. This is true of both the North American version and the Japanese version you're referring to. Unless the translation patch also ports the game from GNROM to oversize BNROM, which I don't find likely due to the file size not being a power of two, you'll need to use a GNROM compatible board. ReproX configured for GNROM uses two flash memories, one for PRG ROM and one for CHR ROM, as opposed to a flash memory for PRG and a 62256 SRAM for CHR RAM.
  3. A 160 KiB ROM without a header should be 163,840 bytes, and a 160 KiB ROM with the 16-byte header should be 163,856 bytes, which is 163,840 + 16. But many file managers round file sizes to the nearest kilobyte or kibibyte. What's the exact size in bytes?

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PostPosted: Tue Jan 29, 2019 8:48 am 
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I know that Dragon Power is GNROM which is why I thought the translated ROM I have was the same, but apparently it is BNROM. Romhacking.net has the patch which says it uses mapper 34 which is BNROM.

The size of the ROM is 160 KB (164,368 bytes) and size on disk says 164 KB (167,936 bytes).

Am I allowed to attach the ROM file? I don't want to break any forum rules.


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PostPosted: Tue Jan 29, 2019 9:16 am 
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160KB doesn't sound like a valid BNROM size... Since BNROM images only contain PRG-ROM, the file size should be a power of 2 (plus the 16-byte header). What you have appears to contain both PRG and CHR images the same size as those from the original game (128KB + 32KB). Also, 160KB + 16 byte header should be 163,856 bytes, but your file is 512 bytes larger than that, which means it likely contains one of those infamous trainers used by disk copiers from back in the day. If this does indeed use a trainer, that probably means you won't be able to easily write this ROM to a cartridge.

Izen6 wrote:
Am I allowed to attach the ROM file? I don't want to break any forum rules.

ROMs containing copyrighted material are not allowed here. You could try uploading a patch that turns the original ROM into the one you have.


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PostPosted: Tue Jan 29, 2019 9:31 am 
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Quote:
160KB doesn't sound like a valid BNROM size... Since BNROM images only contain PRG-ROM, the file size should be a power of 2 (plus the 16-byte header). What you have appears to contain both PRG and CHR images the same size as those from the original game (128KB + 32KB). Also, 160KB + 16 byte header should be 163,856 bytes, but your file is 512 bytes larger than that, which means it likely contains one of those infamous trainers used by disk copiers from back in the day. If this does indeed use a trainer, that probably means you won't be able to easily write this ROM to a cartridge.


The ROM I have does appear to have a trainer. FamiROM does say it has 128KB PRG and 32KB CHR. Using ROM Hasher, it also says it has a trainer. There's no way to get around the trainer?

I've attached the patch file if anyone is able to take a look. Please let me know if I need to take it down. Thanks for your help everyone!


Attachments:
File comment: Dragon Ball - Shen Long no Nazu English Patch
BRC-DB1.IPS [7.24 KiB]
Downloaded 88 times
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PostPosted: Tue Jan 29, 2019 12:26 pm 
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The original is not only a mapper hack that uses a trainer (bad enough) but it's specifically a mapper hack that targets mapper 34's hybrid definition and is simultaneously NINA-001 and BNROM.

The bright side is that this scope of that hack is pretty small, limited to four places where it patches STA abs,Y to JSR $7050. So undoing this is probably doable...


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PostPosted: Tue Jan 29, 2019 12:35 pm 
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lidnariq wrote:
The original is not only a mapper hack that uses a trainer (bad enough)
Who the hell created this mapper hack anyway, and why? It cannot come from an FFE-targeted source, because all Asian RAM cartridges can do GNROM just fine (and the actual FFE/Game Doctor images of this game are not mapper-hacked and do not use a trainer).


Last edited by NewRisingSun on Tue Jan 29, 2019 1:19 pm, edited 1 time in total.

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PostPosted: Tue Jan 29, 2019 12:47 pm 
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lidnariq wrote:
So undoing this is probably doable...
Attachment:


Apply to 'Dragon Ball - Shen Long no Nazo (J) [!].nes', sha1sum b30fcfb27d8e12bd533ef466c4d1080bc1e32713.

Tentatively seems to work for me in an emulator, but no promises.


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PostPosted: Tue Jan 29, 2019 1:43 pm 
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Thanks! Will give it a try when I get home later. Really appreciate everybody's help!


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PostPosted: Tue Jan 29, 2019 5:10 pm 
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So I tried splitting and writing to my eproms and now I do get a picture on the screen, but the graphics are garbled. Is this because I'm supposed to remove the header, or is there something else in play?


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