Reverse engineering the N64 Multi Cart

How we cracked the N64 multi cart and learnt to add our own ROM's...
Not bad for a $12 cart, hundreds of NES/GB/GBC roms, even N64! 128mbytes to work with, 512byte EEPROM, 6102 CIC.
bennvenn.mysho...

[@n64victor30]

Just getting me more excited when I get my joey. Great work 👏 fun video

[@thedarkbanshee]

Got that Java Script ready yet?

[@TheMagpyeTrader]

That's really cool! Awesome job!

[@SpeedDeamon95]

What set up do you have going on there?

[@bennvennelectronics]

The software? HXD hex editor, Ghidra decompiler

[@SpeedDeamon95]

@@bennvennelectronics my bad, I was talking about the electronic hardware/setup. Thanks for the response!

[@bennvennelectronics]

@@SpeedDeamon95 That'll be our Joey N64 cart flasher/dumper. you can find it on bennvenn.com

[@SpeedDeamon95]

@@bennvennelectronics thanks man! Silly question, have you ever thought about remaking the cartridge pcb for a broken N64 game? It wouldnt be hard since its a two sided pcd, just need to desolder all the chips, take pics of both sides and use a program to get the pcb layout/schematic.

[@bennvennelectronics]

@@SpeedDeamon95 We could do that, i think there's only a handful of variations of the PCB used across all PCBs. Nintendo used hard gold plating on the contacts which gets very pricey in low volumes. If there was demand it would be economical but for the odd one-off, maybe not...

[@skins4thewin]

When I clicked on this I thought you were going to be decapping chips & actually reverse engineering the hardware inside the cart. Nothing about this here is reverse engineering tho. You copied the ROM & then fiddled around with it/injected your own code. It's essentially a fan hack you could say, or you could say that you created a different MultiROM image using preexisting code. Nothing about it is considered reverse engineering tho.

[@bennvennelectronics]

Reverse engineering (also known as backwards engineering or back engineering) is a process or method through which one attempts to understand through deductive reasoning how a previously made device, process, system, or piece of software accomplishes a task with very little (if any) insight into exactly how it does so. In this case it was figuring out how the mapper works, mapping addresses, ROM address masking and ultimately using this information to reconstruct a compilation of roms. Sure it's not decapping a CIC but reverse engineering all the same.

[@skins4thewin]

@@bennvennelectronics Ehhhh.... I'm not trying to insult or open a big debate, but your definition is a bit off. Reverse engineering is a fully accurate recreation of something by very exact means, with DEEP and THOROUGH knowledge of how the original works. Reverse engineering is in fact a 100% accurate recreation of something in it's entirety from scratch by dissecting the function of the original down to the basest details. That is pretty much the literal definition. At no time have I ever heard the term be used in the way you're using it. Reverse engineering by definition requires the most meticulous of dissecting of the original work because by definition the end product has to be a 100% accurate re-creation. That's why they call it reverse engineering, because you're dissecting the original to figure out how it works in the first place, without the proper documentation outlining it. If one had those documents then one wouldn't have to reverse engineer it in the first place, they could simply use those records to re-create it. Aka doing the steps in reverse. That's why it's called reverse engineering. Recreating something via intricate dissection & analysis of the original. That is the literal textbook definition. Reverse engineering has helped in the creation of video game Emulators by having the original chips inside the system be reverse engineered, but an Emulator itself is in no way a reverse engineered creation as it is not a recreation of the hardware, and nobody would consider it to be so. By your definition an Emulator would be even more of one than what you did here. I mean I'm not trying to insult you or anything, and the coding changes were impressive, but reverse engineering simply isn't the proper term here. Just saying, really not trying to be mean or anything. Your work has been impressive & I am indeed a fan. I'm just a stickler for detail I guess, at least when its the actual title of the vid aka the very topic of the content. A better title for the video might be something like "Adding extra ROMS to an N64 Multicart", but it definitely isn't what I'd call Reverse Engineering. Even if we were talking code re-creation, what happened here was simply altering the pre-existing code. That's an alteration not reverse engineering. At least that's the way I see it.

[@bennvennelectronics]

You make a fair point. I was just going by the definition in Wikipedia. My goal here was to gain enough information on how the mapper worked to achieve the end goal of inserting ROM's of arbitrary size into whatever location I choose and have the mapper reconfigure the address lines to insert it in the bootable area. I now know how the mapper works and can ask it to do what I want with high confidence so I think I met my goal. I personally consider this reverse engineering, It is ok if you don't. I suppose the purpose of this video is to show others how to manipulate the menu ROM to achieve their own goals. I could have shown my process of deducing what mapper bytes actually did which was 90% of this project but to most this isn't at all relevant. I do appreciate your time to comment and it sounds like we have similar interests. Consider dropping by our discord where we document a lot of this in more detail, happy to discuss further there.

[@skins4thewin]

@@bennvennelectronics It was a neat video for sure, and could certainly be handy for those wanting to create their own custom multicarts. The debate over what reverse engineering is isn't that important to be honest, Potato Potahto lol.

[@user-yk1cw8im4h]

@@skins4thewin bring discuss more. i love watching the world burn