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Generation I Glitch Discussion

Cause of completely corrupted Pokemon Red cartridge? - Page 1

Cause of completely corrupted Pokemon Red cartridge?

Posted by: pikminmovie
Date: 2019-11-13 16:34:00
I had made a reddit post (https://www.reddit.com/r/pokemon/comments/dvl995/help_with_original_pokemon_red_copy/) and couldn't get any extraordinarily helpful answers, so I thought I'd make an account and come here.

I have given more information in the reddit post, but long story short, I picked up a cartridge of red for my Gameboy SP at a local game store. Upon bringing it home and trying it, I quickly figured out that there were some serious issues with the cartridge. A very long, eventually repeating until soft lock, chain of Pokemon cry's and altered town music plays when trying to make a new save file and speak to professor Oak, and resetting save data produces similar effects, with a text box eventually appearing that says "TRAINER9". I have determined that this is not a hardware issue by crosschecking on a different device; still same issue. Here's a link to a video I posted documenting it (unprofessional, sorry, if anyone is interested I can record both Oak and attempting to reset save data fully): https://www.youtube.com/watch?v=ojWdX0sKC-g

Does anyone here have any idea what may be causing this to happen, or if there anything else that I might be able to try/document? Thank you for your patience.

Re: Cause of completely corrupted Pokemon Red cartridge?

Posted by: Parzival
Date: 2019-11-14 00:30:13
Sounds like an MBC fail, as this sounds similar to what happens when you truncate the game to like 512k.

Re: Cause of completely corrupted Pokemon Red cartridge?

Posted by: Sherkel
Date: 2019-11-14 00:52:34
I honestly didn't have a clue, but yes, it sounds like that: https://gbdev.gg8.se/wiki/articles/Memory_Bank_Controllers

You'll notice that while DisplayTextBoxID isn't banked, everything else you're accessing is: https://github.com/pret/pokered/blob/master/main.asm#L17 (the "clear all saved data" function is way down here)

Pretty bizarre to come across on a physical cartridge. Is there any chance you can dump the ROM and post an IPS?

Oh, uhh, Isso gave a much more informative response, by the way.

Re: Cause of completely corrupted Pokemon Red cartridge?

Posted by: Torchickens
Date: 2020-03-06 12:27:56

I had made a reddit post (https://www.reddit.com/r/pokemon/comments/dvl995/help_with_original_pokemon_red_copy/) and couldn't get any extraordinarily helpful answers, so I thought I'd make an account and come here.

I have given more information in the reddit post, but long story short, I picked up a cartridge of red for my Gameboy SP at a local game store. Upon bringing it home and trying it, I quickly figured out that there were some serious issues with the cartridge. A very long, eventually repeating until soft lock, chain of Pokemon cry's and altered town music plays when trying to make a new save file and speak to professor Oak, and resetting save data produces similar effects, with a text box eventually appearing that says "TRAINER9". I have determined that this is not a hardware issue by crosschecking on a different device; still same issue. Here's a link to a video I posted documenting it (unprofessional, sorry, if anyone is interested I can record both Oak and attempting to reset save data fully): https://www.youtube.com/watch?v=ojWdX0sKC-g

Does anyone here have any idea what may be causing this to happen, or if there anything else that I might be able to try/document? Thank you for your patience.


Yes, it might be a cart fault (such as memory bank controller/MBC fail) that's speculated to be why Oak turns into Gastly; because  the game is stuck on the bankless memory region and the Oak intro is meant to use the banks; so it runs the wrong code causing the seemingly random glitch (because the game cannot differentiate code and data automatically). You're not alone too https://www.youtube.com/watch?v=FyXVd_lpjRQ

Long answer, the Game Boy uses the MBC for Pok√©mon Red, and only 0000 to 0:4000-0:7FFF can be accessed from the ROM at a time. What the MBC does allows the game to grab data from other parts of the ROM, such as 1:4000, 2:4000, and others. In order to convert a pointer into an offset, we follow the guide here https://datacrystal.romhacking.net/wiki/Pointer Each three byte pointer (Y:XXXX) represents what is referred to as an offset, and is the exact location in a hex editor; but for the most part not the game while it is running.