Discussion about software development for the old-school Gameboys, ranging from the "Gray brick" to Gameboy Color
(Launched in 2008)
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Hi guys,
I am attempting to build my original Gameboy into a computer and use a Raspberry Pi board inside it for the main bones of the thing. This is not a problem, however on a whim I thought it would be a cool idea if I could get the screen that is already in the Gameboy to display the Raspberry Pi logo in dot matrix form or something along those lines.
My question is this, is it possible to reprogram the LCD display (or possibly the script that shows the nintendo logo on startup) on the original Gameboy to show a different or a constant image? I can always replace the screen with a more modern controller but for originalities sake I would really rather keep the screen that was my childhood in its rightful place
Thanks guys any help is really appreciated as this is my first Gameboy project!
Tom
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someone help him
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I think your best bet might be hacking the Gameboy BIOS. The hack should:
1.- Disable the Gameboy logo check on the cartridge header.
2.- Replace the Nintendo logo with the one you want to show.
Maybe step (1) is not needed, supposing you have room in the BIOS ROM to store both the original Nintendo logo and your custom logo. But if there is no room, you'll have to do both steps.
Unfortunately I cannot help you disassembling and hacking the BIOS, but I would not be surprised if somebody has already done this. I remember a similar hack that replaced the Nintendo logo with a custom one, by using a cart with a custom made MBC1 emulator, but as I suppose you are not using GB carts, I'd go for the BIOS hack.
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The BIOS is mask ROM inside the CPU. So replacing it is out of the question for most people.
You will need a PLD and some free space in your flash to pull of a logo-switching trick. The Gameboy makes the cardinal sin of reading the logo twice: once to show it on-screen, once to compare for legitimacy. You send the logo you want on-screen in one iteration of the BIOS reading the logo, you send the original Nintendo logo in the next iteration.
cYa,
Tauwasser
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Tauwasser wrote:
The BIOS is mask ROM inside the CPU. So replacing it is out of the question for most people.
I thought what he wants is to fit a RPi inside a Gameboy case, and use an emulator. If that's the case, he should be able to use a hacked BIOS with the emulator without a problem.
But I have re-read the original post, and I think he does not want the "Pi-Boy" to boot into a GB emulator, but to a Linux desktop/shell/whatever. If that's the case, it should be a lot easirer. Again I cannot give you the details, but you just need to install and configure one of these (some of them may not be supported by the RPi, you'll have to investigate a bit):
- fbsplash
- Splashy
- Plymouth (this one is maybe the best, but requieres hardware support)
- XSplash
These programs also support animations, so you should be able even to move the logo like in the original Gameboy. Unfortunately, playing the sound might be a lot harder (at least if you want to sync it with the animation).
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