Extracting the GameBoy ROM from photographs of the die

https://github.com/travisgoodspeed/gbrom-tutorial

by pabs3 • 3 years ago

407 46 3 years ago

github.com

captainkrtek• 3 years ago

This is fantastic. Love these kinds of deep technical adventures

jtchang• 3 years ago

How many bits are in a gameboy rom? How do you even take a picture of a rom?

JonathonW2• 3 years ago

With a microscope, after removing the packaging of the chip (with nitric acid, in this case). The readme in the linked repo goes into detail both on how they produced the image used, and how the image is used to extract the ROM.

The ROM itself is 256 bytes, and has been previously extracted using a similar technique. The last thing it does on boot (before moving on to the cartridge’s entry point, which is adjacent) is remove itself from the system’s address space, so special techniques like this are needed to extract it (can’t just do it from normal Game Boy code).

ilikehurdles• 3 years ago

I believe you mean 256kilobytes? Even at 90s handwritten assembly standards, 256 bytes seems too small for basic games.

ChickeNES• 3 years ago

The ROM itself is 256 bytes, and has been previously extracted using a similar technique.

Actually, it was originally extracted via clock glitching to cause the CPU to skip the instruction that unmaps the bios

codyd51• 3 years ago

Might be of interest to folks in this thread: I wrote about the GameBoy boot ROM here: https://axleos.com/writing-axles-gameboy-emulator/

twawaaay2• 3 years ago

You take picture of a ROM because in the past we did not have technology to have permanent non-volatile storage on a chip. We later had eproms and eeproms which were programmable and re-programmable but they were also expensive and problematic.

So the main solution to have any programming on the chip was to actually etch it permanently. That's why we can read it today.

fallat• 3 years ago

It's also why it make sense to collect Game Boy games - they'll be playable for basically ever :D

gumboshoes• 3 years ago

Extraordinary. I love other people's well-explained expertise even if I have no use for it whatsoever.

nrabulinski• 3 years ago

I love Travis’ work. Had the pleasure of meeting him last year in Stockholm. Not only does he have fascinating and engaging talks he’s super cool and down to earth.

nezza-_-• 3 years ago

The Game Boy ROM is so much fun to dump in various ways. For example you can clock glitch it by just by scraping a contact with a jumper wire: https://youtu.be/64FgfhfvJ4s?t=154

Medox• 3 years ago

Fun fact: in the save video, you can see Neviksti's photographs of the die from 2003 (https://youtu.be/64FgfhfvJ4s?t=256)

tacker2000• 3 years ago

Wow this is really cool!

sour-taste• 3 years ago

In the past when I've had to identify grids opencv worked well. Specifically the edge finding pretty reliably identified the grid. I wonder if it could work here? Maybe I provide a guide that the user can later edit?

svendahlstrand• 3 years ago

Shameless self-promotion: if you enjoyed Travis' ROM dumping, you might find my piece about sniffing the Game Boy's LCD data bus to take screenshots interesting as well.

https://github.com/svendahlstrand/game-boy-lcd-sniffing

wkjagt• 3 years ago

This is really amazing, thanks for sharing! How did you know which pins to look at? And do you know what the other pins do? I’m super curious now, and actually have an original gameboy which I now want to open up :-)

I wonder if these same signals can be used to make an adapter to connect an external screen.

HopenHeyHi• 3 years ago

You figure out which pins to look at by time consuming painstaking trial and error. :)

circuit10• 3 years ago

Something that I think is even more interesting is that someone made a screen capture device that would go between the cartridge and the console and work only based on what code the game was accessing by reconstructing the entire state of the Game Boy based on what paths were taken in the code

https://there.oughta.be/a/game-boy-capture-cartridge

miduil• 3 years ago

So cool and really love that people still found even less intrusive ways to capture gameplay:

https://there.oughta.be/a/game-boy-capture-cartridge

https://news.ycombinator.com/item?id=34069305

causi• 3 years ago

A biological microscope will not work, because the silicon substrate is opaqe to visible light; in a metallurgical microscope, the light reflects off of the sample rather than transmitting through it.

Is there a reason you couldn't just use a biological microscope and add top=-illumination yourself?

ckocagil• 3 years ago

You can if there's enough space between the lens and the die.

hashhar• 3 years ago

Anyone who liked this would probably also find https://www.youtube.com/watch?v=6mOJtrFnawk very interesting.

v-erne• 3 years ago

Wow that's amazing - he actually created almost an entire gameboy just to "capture" video signal from gameboy. Its astonishing and terrifying at the same time. And rises some interesting philosophical questions (if he managed to create perfect emulation is this really video capture from the point of view of user or something wholly different)

tmountain3• 3 years ago

I love stuff like this. I saw something loosely related a while back where someone had taken apart an old kids toy (the atomic powered robot), and it had a little plastic disc inside for a the sound and voice effects.

They were able to play it back by taking a high resolution photo and decoding the image.

This feels like magic to me no matter how well I understand the science behind it.

userbinator• 3 years ago

a little plastic disc inside for a the sound and voice effects

It took me longer than expected to realise you were talking about a phonograph record.

tmountain3• 3 years ago

Not vinyl though, but yeah…

amelius• 3 years ago

Then you will like the recovery of sounds from ancient pottery.

tmountain3• 3 years ago

Nice try…

ipunchghosts• 3 years ago

Travis is amazing

lapinot• 3 years ago

Very cool. Although bit recognition could be made more robust by using information from all three channels instead of just one. Eg by projecting on the principal component and applying the threshold there.

Extracting the GameBoy ROM from photographs of the die

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