Re: Rom header hacking basics? (The Dumper)

>

-------------------------------------------------------------------------------
> 4. FILE HEADER
> -------------------------------------------------------------------------------
>    1) CREATED BY JSI/FRONT FAREAST.
>    2) 512 BYTES LENGTH. (ONE SSECTOR)
>    3) BYTE
>        0   - LOW BYTE OF 8K-BYTES PAGE COUNTS.
>        1   - HIGH BYTE OF 8K-BYTES PAGE COUNTS.
>        2   - EMULATION MODE SELECT
>              BIT 76543210
>                  X        : 1=RUN IN MODE 0. (JUMP $8000)
>                   X       : 0=LAST FILE OF THE GAME. (MULTI FILE LOADING)
>                    X      : 0=MODE 1, 1=MODE 2. (SRAM MAPPING)
>                     X     : 0=MODE 20, 1=MODE 21. (DRAM MAPPING)
>                      XX   : 0=SRAM OFF, 1=SRAM 16K, 2=SRAM 64K, 3=SRAM 256K
>                        X  : 0=RUN IN MODE 3, 1=RUN IN MODE 2. (JMP RESET)
>                         X : 0=DISABLE, 1=ENABLE. (EXTERNAL CARTRIDGE MEMORY
>                                                   IMAGE AT BANK 20-5F, A0-DF
>                                                   IN SYSTEM MODE 2, 3)
>        3-7 - RESERVED. (SHOULD BE '00')
>        8   - FILE ID CODE 1. (SHOULD BE 'AA')
>        9   - FILE ID CODE 2. (SHOULD BE 'BB')
>        10  - CHECK THIS BYTE IF ID 1 AND 2 MATCH.
>              '02': MAGIC GRIFFIN GAME FILE. (PC ENGINE)
>              '03': MAGIC GRIFFIN SRAM DATA FAILE.
>              '04': SWC&SMC GAME FILE. (SUPER MAGICOM)
>              '05': SWC&SMC PASSWORD, SRAM DATA, SAVER DATA FILE.
>              '06': SMD GAME FILE. (MEGA DRIVE)
>              '07': SMD SRAM DATA FILE.
>        11-511 - RESERVED. (SHOULD BE '00')

> Just used the 'pre' html tag for pre-formatted text :)

> Anyways, I still don't really get it...

> 1) WTF is a 8K Page count??
> 2) What is 'Mode 0', 'Mode 1', 'Mode 2', 'Mode 3', 'Mode 20' and 'Mode 21'? How do you find out if a game uses one of them? Or are they Console specific Modes (like one different mode for Megadrive, SNES and PC-Engine games)?
> 3) What is 'external cartridge memory'?

> -- Matthias

8K byte page count is... how many 8K byte pages the game uses. So take the game size divided by 8K and that's what you put there.

I not sure about the rest but what you do if you want to get a game running is find another compatible game that you know has a good header and usually all you have to fix up is the sram size. So if the game that gets a copy protection message is 16Kb LoRom, 16K sram, look for another 16Kb LoRom 16K sram game (that you know has a good header) and copy the header over.

Oh, and it's not just external cartridge memory, you left off the rest. It's EXTERNAL CARTRIDGE MEMORY IMAGE AT BANK 20-5F, A0-DF. This probably indicates a LoRom memory mapping.

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Message	> > Well, here's how it should look like... > > <pre>------------------------------------------------------------------------------- > > 4. FILE HEADER > > ------------------------------------------------------------------------------- > > 1) CREATED BY JSI/FRONT FAREAST. > > 2) 512 BYTES LENGTH. (ONE SSECTOR) > > 3) BYTE > > 0 - LOW BYTE OF 8K-BYTES PAGE COUNTS. > > 1 - HIGH BYTE OF 8K-BYTES PAGE COUNTS. > > 2 - EMULATION MODE SELECT > > BIT 76543210 > > X : 1=RUN IN MODE 0. (JUMP $8000) > > X : 0=LAST FILE OF THE GAME. (MULTI FILE LOADING) > > X : 0=MODE 1, 1=MODE 2. (SRAM MAPPING) > > X : 0=MODE 20, 1=MODE 21. (DRAM MAPPING) > > XX : 0=SRAM OFF, 1=SRAM 16K, 2=SRAM 64K, 3=SRAM 256K > > X : 0=RUN IN MODE 3, 1=RUN IN MODE 2. (JMP RESET) > > X : 0=DISABLE, 1=ENABLE. (EXTERNAL CARTRIDGE MEMORY > > IMAGE AT BANK 20-5F, A0-DF > > IN SYSTEM MODE 2, 3) > > 3-7 - RESERVED. (SHOULD BE '00') > > 8 - FILE ID CODE 1. (SHOULD BE 'AA') > > 9 - FILE ID CODE 2. (SHOULD BE 'BB') > > 10 - CHECK THIS BYTE IF ID 1 AND 2 MATCH. > > '02': MAGIC GRIFFIN GAME FILE. (PC ENGINE) > > '03': MAGIC GRIFFIN SRAM DATA FAILE. > > '04': SWC&SMC GAME FILE. (SUPER MAGICOM) > > '05': SWC&SMC PASSWORD, SRAM DATA, SAVER DATA FILE. > > '06': SMD GAME FILE. (MEGA DRIVE) > > '07': SMD SRAM DATA FILE. > > 11-511 - RESERVED. (SHOULD BE '00')</pre> > > Just used the 'pre' html tag for pre-formatted text :) > > Anyways, I still don't really get it... > > 1) WTF is a 8K Page count?? > > 2) What is 'Mode 0', 'Mode 1', 'Mode 2', 'Mode 3', 'Mode 20' and 'Mode 21'? How do you find out if a game uses one of them? Or are they Console specific Modes (like one different mode for Megadrive, SNES and PC-Engine games)? > > 3) What is 'external cartridge memory'? > > -- Matthias > 8K byte page count is... how many 8K byte pages the game uses. So take the game size divided by 8K and that's what you put there. > I not sure about the rest but what you do if you want to get a game running is find another compatible game that you know has a good header and usually all you have to fix up is the sram size. So if the game that gets a copy protection message is 16Kb LoRom, 16K sram, look for another 16Kb LoRom 16K sram game (that you know has a good header) and copy the header over. > Oh, and it's not just external cartridge memory, you left off the rest. It's EXTERNAL CARTRIDGE MEMORY IMAGE AT BANK 20-5F, A0-DF. This probably indicates a LoRom memory mapping.
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