Dumping Bioses

[l_oliveira]

Well, I gotta comment that the CD1 has a small heatsink but the IC it uses for 5V conversion is slightly better in efficiency department than the plain 7805 IC.

I would avoid using a prototype console as wearing it down you are reducing it's value. It's a historical item.

[BKK]

Yeah, I wasn't planning on using it very often. Bios dumped now;

http://assemblergames.com/l/threads/...er-1-11.64045/

[zyrobs]

If you still have it disassembled, could you please make some screenshots of various parts of the board, and the ICs? Especially the bios chip, I can't quite read the markings on it.

edit: does the Megadrive have a serial sticker on its back?

[BKK]

Yeah, I'll document the various ICs when I get the bios chip back. The Mega Drive doesn't have any stickers on it.

[zyrobs]

Sounds great!

And thanks for dumping and sharing the bios chip!

[kamillebidan]

My "Transfer Suite" works fine with my region converter tool. Be warned that there is a small flaw in that there are a couple of bytes from the BIOS that are overridden by a register value when read from the normal address. I should really update it to read from a mirror instead. This doesn't really matter for actually using the dumped BIOS, but if won't technically be bit perfect to what's in the ROM.

For what it's worth, it should be pretty straightforward to write a dumping tool for a more recent flash cart, especially one like the Mega Everdrive that has a USB serial connection.

Could you be more specific on which bytes need to be read from somewhere else?
I wrote a dumper
http://www.sega-16.com/forum/showthr...CD-bios-dumper
and my dumps are either undumped versions or suffer for the problem you mention.
From what you say I believe it's the latter, so I'd like to fix that.

[Pha]

My "Transfer Suite" works fine with my region converter tool. Be warned that there is a small flaw in that there are a couple of bytes from the BIOS that are overridden by a register value when read from the normal address. I should really update it to read from a mirror instead. This doesn't really matter for actually using the dumped BIOS, but if won't technically be bit perfect to what's in the ROM.

For what it's worth, it should be pretty straightforward to write a dumping tool for a more recent flash cart, especially one like the Mega Everdrive that has a USB serial connection.

You plan to update your "suite" what good news, on this subject an option of the choice of the communication port (controller port 1 or 2 and "ext" of the firsts md...) would be welcome !

[deadscreem]

Yeah, I wasn't planning on using it very often. Bios dumped now;

http://assemblergames.com/l/threads/...er-1-11.64045/

anyone that have this file can repost now that assembler is dead?

edit: nvm, its here
https://segaretro.org/Sega_Mega-CD/Boot_ROM

It should be noted however, that this is not in any way a prototype model 2 bios. 1.11 is just the last version of the original model 1 japan bios. and its a really rare version. I've only seen it in an actual japan model 1 once in my life. I believe it was never on factory units, and only found on units that were sent to sega for repair.

https://segaretro.org/images/2/2e/Se..._Bulletins.pdf
lists the header of the last japan model 1 cd bios, the checksum given $f074, is the same as this. So its definitely not a prototype model 2 BIOS.

[Nano Babe]

anyone that have this file can repost now that assembler is dead?

edit: nvm, its here
https://segaretro.org/Sega_Mega-CD/Boot_ROM

It should be noted however, that this is not in any way a prototype model 2 bios. 1.11 is just the last version of the original model 1 japan bios. and its a really rare version. I've only seen it in an actual japan model 1 once in my life. I believe it was never on factory units, and only found on units that were sent to sega for repair.

https://segaretro.org/images/2/2e/Se..._Bulletins.pdf
lists the header of the last japan model 1 cd bios, the checksum given $f074, is the same as this. So its definitely not a prototype model 2 BIOS.

actually my mega CD is V1.11 model 1 interesting that it could be a refurbished unit from Sega how did you come to that assumption? I can confirm that it contains the JVC laser and the main board is slightly different with an extra populated Chip ( top right ) which is left out of a PAL UK unit which just has the empty space on the main board see Photo

Attachment 15372