Firmware/BIOS

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Cassiel
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Firmware/BIOS

Post by Cassiel » Mon Aug 20, 2012 5:36 pm

Guys, I'm in need of your expertise...

I'm working my way through all the posts here (there is a wealth of useful information here!) and have made a few amendments to the current TOSEC DC Firmware DAT.

It now currently stands like this:
5454841f Sega Dreamcast BIOS v1.004 (1998)(Sega)(JP)(M6).bin
a2564fad Sega Dreamcast BIOS v1.01d (1999)(Sega)(EU)(M6).bin
89f2b1a1 Sega Dreamcast BIOS v1.01d (1999)(Sega)(M6).bin
786168f9 Sega Dreamcast BIOS v1.022 (1999)(Sega)(US)(M6).bin
485877bd Sega Dreamcast Development Box HKT-0120 BIOS v0.74 (1998)(Sega)(beta).bin
2186e0e5 Sega Dreamcast Development Box HKT-0120 BIOS v1.011 (1999)(Sega)(M6).bin

I've added the recent non-MIL BIOS (http://dumpcast.thekickback.com/forum/v ... php?t=1310), and amended 89F2B1A1 to be non-region specific (as is my understanding re http://dumpcast.thekickback.com/forum/v ... .php?t=499). I've left 5454841F as JP since I believe this has been found in early Japanese DC's only. A2564FAD I've left as EU since I haven't found any info either way for this dump.

Does the above look accurate to you guys?

I'm especially interested in any new dumps or confirming existing dumps/assumptions that might have occurred since when I originally created (and had control of!) this DAT so many years ago.

Also, are the revisions correct? I've notice you reference the 'Kabuto' version in regards to v1.xx, but overall refer to the revision as v2.xx?

Additionally, what's the current situation regarding dumps of the Flash ROM? When I originally aimed to include these as well, there was only a mess of 'used' or hacked dumps available. Are there any 'clean' untouched dumps now? From my failing memory, none of the 'Flash Reset' tools REALLY reset the ROM to factory default, not properly. Is there even any point even looking at these anyway, if they (hypothetically) just 128k of FF's minus the 1 byte that signals J/U/P/A/B region?

Any thoughts, opinions or pointing of fingers greatly appreciated...
Cassiel
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Joined: Wed May 02, 2012 10:30 pm

Post by Cassiel » Mon Aug 27, 2012 12:47 pm

Guys...?
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Maddog
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Post by Maddog » Tue Aug 28, 2012 5:07 pm

Hi there Cassiel, been away for a while so replying now.
I am not an expert on the BIOS, but here are a few things I know for sure:

89f2b1a1 Sega Dreamcast BIOS v1.01d (1999)(Sega)(M6).bin
Got this one by dumping from my own PAL Dreamcast so it's definitely a non-region specific BIOS. IIRC, ackmed got the same from his USA DC back then.

5454841f Sega Dreamcast BIOS v1.004 (1998)(Sega)(JP)(M6).bin

Legit, as far as I can tell. Probably only early Japanese as you say.

a2564fad Sega Dreamcast BIOS v1.01d (1999)(Sega)(EU)(M6).bin
No idea about that, as I told already mine had the 89f2b1a1 BIOS. Could be a hack? Where did it come from?

No idea at all about the DevBoxes.
Also, are the revisions correct? I've notice you reference the 'Kabuto' version in regards to v1.xx, but overall refer to the revision as v2.xx?
Not sure what you mean here, but the version can be found by looking at BIOS with a hexeditor, near the start of the file (offset 000007B0). This is contained there for the Japanese bios 5454841f:

Code: Select all

SEGA SEGAKATANA  KABUTO Ver.1.004 Copyright(c) SEGA ENTERPRISES, LTD., 1998     
Regarding the "flash" ROM: it's still a mess and I don't think a factory clean dump can be acquired with any easy method, sort of dumping the chip directly from a brand new DC. Even if using httpd-ack on a brand new DC, it would still alter the settings to accomodate the BBA.

But difference on Flash is not just one byte between regions. This was true for some circulating Flash roms, where the "JAP" and "US" were later proven as coming from a hacked PAL Flash. Some japanese and US .gdi games were still able to detect that and wouldn't boot using this Flash (though most were fooled). Later on, some legit US and JP flashes were circulated and those games were booting correctly on those (I personally tried that)
I have still on my HDD both versions, if you wish to examine them I can send them over.

Hope I have helped, but definitely others know more on the subject... :?
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executter
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Post by executter » Mon Sep 10, 2012 8:27 am

Bios with crc a2564fad seems to be a 'poor' translation in chinese (Treamcast ?).
Japanese language was replaced by chinese, but some references to japanese are always there.

English to chinese option was correctly translated :
Image
Not for others languages :
Image



Bios with crc 5454841f refers to early japanese units, the revision 0 (or VA0 for mainboard).
Just to point out that we can find revision 0 in NTSC-U and also PAL units ! (seen one on ebay) :
In ASSEMblergames' forums, I have already heard that NTSC-U 0 has same bios than NTSC-J 0, but no real proof with CRC comparaison.
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atreyu187
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Post by atreyu187 » Tue Sep 11, 2012 3:39 pm

Thanks that is mighty interesting and i bet it came from the treamcast. And the non mil cd bios can only be found in rev 2.1a boards in ntsc-u dreamcast made in japan after October 2000. The Chinese made models never got this updated bios till after sega killed the dreamcast. And the kabuto is at another number between the usa and japanese bios.The kabuto on the 2.1a is just one increment above the v2 usa bios.
Cassiel
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Post by Cassiel » Fri Sep 14, 2012 7:04 pm

Maddog wrote:Hi there Cassiel, been away for a while so replying now.
I have still on my HDD both versions, if you wish to examine them I can send them over.
Actually that might be useful... cheers.
Cassiel
Posts: 29
Joined: Wed May 02, 2012 10:30 pm

Post by Cassiel » Fri Sep 14, 2012 7:08 pm

Thanks for all the info guys.... has been VERY useful.
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