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Gameboy Color Boot ROM Dumped After 10 Years
An anonymous reader writes "Costis was able to dump the elusive boot ROM from the Gameboy Color by using various voltage and clock glitching tricks. The boot ROM is what initializes the Gameboy hardware, displays the 'GAMEBOY' logo and animation, and makes the trademarked 'cling!' sound effect. Even decapping the CPU had failed previously, but now the boot image and specifics on how it was dumped (along with many photos) are available for download."
I really love reading about the lengths enthusiasts go to when trying to do this kind of thing. For some reason I had assumed that this had been done already since there is already emulation for gameboy color, right? Can someone explain the significance of this development?
The gameboy bios was also "emulated" before, so this makes the emulation more "realistic". It happens the same with the GBA. While you can emulate games for the GBA without the need for a BIOS file, if you have one, they'll run better \ more accurately (or in some cases, they run instead of not running).
This allows Game Boy Color emulators to display an authentic intro before running the game, including the palette selection available when running a non-color game. There's otherwise no benefit that I can see. This includes initial register values, since those could already be determined via software. Some of the other initial state, like sound registers set by the boot ROM, is more difficult to determine, so this helped there.
When reverse-engineering hardware, it's nice to figure out every detail, and this was one of the much harder ones to figure out. Decapping usually reveals all, but even that failed here.
Why a few seconds, why not an exact time?
Because that's the degree of precision necessary when working with analog electronics that aren't intended to function as timing devices. Anything more precise would be unnecessary, anything less would be insufficient.
I am a geek attorney, but not your geek attorney unless you've already retained me. This is not legal advice.
I believe he also had to short the 3.3V rail to ground during the time the clock is stopped, to randomize the registers values.
Because the boot ROM is built into the custom CPU. The data bus to this ROM isn't exposed on any of the pins; when enabled, it bypasses whatever is being sent to the external data bus pins on the CPU, so that its contents are never seen by the outside world.
A close comparison is the L1 cache inside a modern CPU. When the CPU is reading from it, you can't know what is in it, since the data isn't output to the bus.
Copyright lasts 70 years, not 10. And you don't need to add a copyright notice to get copyright. If you made it it's yours, under your copyright. If something has no notice/license at all, then it's copyrighted. And then you shouldn't go and copy it.
http://inventors.about.com/od/copyrights101basicsfaq/f/secure_copyrigh.htm
I like how this is modded +5 Informative when it is entirely made up.
I assume you refer to the United States. The US was actually late to the party. The Berne Convention got the ridiculous-copyright-term ball rolling... Disney just gave it an extra push. In particular:
The Berne Convention is also what gives us the rule that daid303 stated, that you don't need to add a copyright notice to get copyright:
The US didn't sign on to Berne until 1988. The EU's been on board for awhile, as have many, many other countries. So, yes, you're technically correct that there are some people that are unaffected by the US's copyright protections (or in the case of Nintendo's IP, Japan's). But, a great many places have similar restrictions.
Program Intellivision!
This article is a classic example of why you shouldn't take legal advice from slashdot posts.
Note, I am not a lawyer, but that doesn't mean I can't find credible sources/links which show this guys doesn't know jack nor shit about what he's talking about.
First, yes, as someone pointed out, copyright laws vary somewhat from country to country. However, thanks to treaties, like the Berne Convention, which has been signed by most of the world's countries (although, not all the countries necessarily enforce it vigorously) they have become fairly standardized.
For the following statements, I've referenced wikipedia articles (which, I suppose might be wrong, but I have a fair amount of confidence in the accuracy), as well as the US Copyright Office website:
1) Copyright is longer than 10 years in most countries, and particularly, in the US, Europe and Japan (50 years for Japan, 70 years for US and Europe). So there is no way this is public domain (note: I am, personally of the opinion that copyright on software *should* be about 10 years, maybe renewable for another 10, but want you or I want, and what is law, are two separate things, and you'd do well to remember that).
2) You don't have to bother to copyright something. In all Berne Convention copyright regimes, copyright is *automatic* at the moment a work is put in a fixed form. So,
"But technically, is it even copyrighted if he didn't submit it to the Copyright Office, or is it just a banner he put there to scare people?"
Yes, to the extent that something he claims copyright on is actually his original work, it *is* copyrighted. Whether he'll enforce the copyright or not, is a different question, which I cannot answer.
There is a hashtable of GameBoy Mono games which are recognized by the GameBoy Color, and it applies a preset color scheme that Nintendo chose to make the game stand out better. Metroid II is a perfect example of this coloring. All of these GBC colored B&W games are run in plain B&W mode, even if they have Super GameBoy features, as the GBC is not a Super GameBoy and doesn't have the same features. There is a disassembled source file to the GBC Boot ROM linked on the dumper's website, with most of it commented and disassembled. (Except the game recognition hashing part, which is still being analyzed)