Game Boy bootroms

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scyther-grovyle
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Game Boy bootroms

Post by scyther-grovyle » 16 Jun 2016 08:29

There was the recently added early Game Boy bootrom, dumped by Gekkio, but that's not the only one missing in Dat-O-Matic. There is also one for the Game Boy Pocket (MGB), Super Game Boy and Super Game Boy 2.

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Tauwasser
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Re: Game Boy bootroms

Post by Tauwasser » 17 Jun 2016 16:05

I already talked about the submission process with gekkio. Maybe he'll submit himself or I'll pester him about it some more ;)

gekkio
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Re: Game Boy bootroms

Post by gekkio » 04 Jul 2016 20:57

I finally managed to register here 8-)

The original source of the MGB boot ROM can be found from web.archive.org: http://web.archive.org/web/201412091543 ... om/MGB.htm
That site also has an independent verification of the common DMG Rev 1 boot ROM.

The Super Game Boy boot ROM actually already exists in Dat-o-matic...it's just on the SNES side with the name "[BIOS] SGB-CPU (World)".
A similar entry could be added for the CPU SGB2 chip. The details about the boot ROM are in my blog: http://gekkio.fi/blog/2015-09-13-dumpin ... t-rom.html

How do redumps work with boot ROMs? I don't know about the standard procedure here, but I would imagine redumps from different people or different chip revisions would be useful.
If it's useful, I can dump the SGB, MGB, and DMG boot ROMs for verification purposes. AFAIK there is only a single revision of the SGB, MGB, and SGB2 chips, but DMG has at least 5 revisions (original, A, B, C, blob).
The blob might be just C in a different package, or might consist of multiple revisions, but distinquishing between them is problematic because there is no text on the chip at all.
In any case, I think it would be valuable to document that A, B, C, and blob all use the same boot ROM if it's true.

I also have almost all CGB/AGB/AGS revisions, but CGB is tough to dump and the Game Boy boot ROMs of AGB/AGS have AFAIK never been dumped before and no working technique exists.

It's a bit off topic, but what about Game Boy games? I've got maybe 40 games or so that I can redump. What's the procedure and what kind of information should I produce? Should I include photos?

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C. V. Reynolds
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Re: Game Boy bootroms

Post by C. V. Reynolds » 16 Jul 2016 14:54

Redumps for verification are always helpful, including with boot roms.

gekkio, thank you doing your research and sharing your findings and data. I hold preservationists in high regard.

Hiccup
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Re: Game Boy bootroms

Post by Hiccup » 17 Jul 2016 10:51

and photos are definitely wanted

gekkio
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Re: Game Boy bootroms

Post by gekkio » 23 Oct 2016 13:09

It took me a while to hunt down the remaining CPU versions, but I now have all the known Game Boy CPUs (excluding the Game Boy Micro CPU AGB E).
I spent some time redumping all the different DMG/SGB/MGB/SGB2 versions, so here are the redump results and photos of CPUs and units where applicable.

Up next: CGB/AGB boot ROM dumping, GB/GBC game redumps (I've got ~30 done, and maybe another 30 in the queue).

[BIOS] Nintendo Game Boy Boot ROM (World)

I don't know which DMG-CPU unit I used in my original dump, so in my opinion the original entry should be removed, and these two should be added.

DMG-CPU

CPU: http://gekkio.fi/files/boot-rom-dumping/cpu_dmg.jpg
Unit: http://gekkio.fi/files/boot-rom-dumping/unit_dmg.jpg

DMG-CPU (LR35902)

For the sake of completeness, I also dumped this earlier version which includes the text "LR35902" on the silk screen. I don't think the CPU itself is any different.

CPU: http://gekkio.fi/files/boot-rom-dumping ... r35902.jpg
Unit: http://gekkio.fi/files/boot-rom-dumping ... r35902.jpg

[BIOS] Nintendo Game Boy Boot ROM (World) (Rev 1)

DMG-CPU A

CPU: http://gekkio.fi/files/boot-rom-dumping/cpu_dmg-a.jpg
Unit: http://gekkio.fi/files/boot-rom-dumping/unit_dmg-a.jpg

DMG-CPU B

CPU: http://gekkio.fi/files/boot-rom-dumping/cpu_dmg-b.jpg
Unit: http://gekkio.fi/files/boot-rom-dumping/unit_dmg-b.jpg

DMG-CPU C

CPU: http://gekkio.fi/files/boot-rom-dumping/cpu_dmg-c.jpg
Unit: http://gekkio.fi/files/boot-rom-dumping/unit_dmg-c.jpg

DMG-CPU X (blob)

CPU: http://gekkio.fi/files/boot-rom-dumping/cpu_dmg-x.jpg
Unit: http://gekkio.fi/files/boot-rom-dumping/unit_dmg-x.jpg

[BIOS] SGB-CPU (World)

SGB-CPU 01

The clock scraping method doesn't seem to work on SGB/SGB2, but I have this CPU chip soldered to a test board where I have full control so dumping was still possible.
So, the board is blue because the chip is not on the original SGB board.

CPU: http://gekkio.fi/files/boot-rom-dumping/cpu_sgb.jpg

[BIOS] Nintendo Game Boy Pocket Boot ROM (World)

CPU MGB

CPU: http://gekkio.fi/files/boot-rom-dumping/cpu_mgb.jpg
Unit: http://gekkio.fi/files/boot-rom-dumping/unit_mgb.jpg

[BIOS] SGB2-CPU (Japan)

CPU SGB2

I didn't actually redump this, but this is the unit I used in my previous dump. So don't add a new entry, but you can add the photo to the existing entry if you want.

CPU: http://gekkio.fi/files/boot-rom-dumping/cpu_sgb2.jpg

KingMike
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Re: Game Boy bootroms

Post by KingMike » 24 Oct 2016 03:32

I'm surprised about that yellow DMG console supposedly from 1998. They were still making the original model? I'd have thought it would've been completely discontinued for the Pocket (with the Color almost if not finally released).

gekkio
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Re: Game Boy bootroms

Post by gekkio » 24 Oct 2016 11:27

KingMike wrote:I'm surprised about that yellow DMG console supposedly from 1998. They were still making the original model? I'd have thought it would've been completely discontinued for the Pocket (with the Color almost if not finally released).
I too was surprised by this...My earliest Pocket is from 1996 and earliest Color from 1998, but this particular DMG has chips from 1997-1998 and the mainboard and LCD board stamps indicate it was actually put together in 1999!
Also, all of my 1997 DMGs are blobs, so DMG CPU C came very very late and is present in very few units. It's also interesting why they would manufacture DMG CPU C at all since it came after the blobs. My earliest blob DMG is from 1995, so after around three years of blobs they went back to normal chip packaging with DMG CPU C. Why?

I think the answer might actually be very simple: warehouses and surplus old stock. The blob chips are only compatible with the blob boards (DMG-CPU-07, DMG-CPU-08), so I think Nintendo had a lot of DMG-CPU-06 boards around and wanted to empty the warehouses by selling those. My initial research suggests that DMG CPU C might be the same chip as MGB/SGB2 but with a different boot ROM and a DMG-compatible pinout (probably just different bonding wire placement). So, I think they manufactured a small amount of DMG CPU C with the same technology as MGB/SGB2 in order to get rid of the remaining boards. Manufacturing DMG CPU B with old technology would probably have been more expensive than manufacturing DMG CPU C by applying these simple changes with the new technology.

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