I don't think Game Genie was sold, I think it just died when the US distributor, toy company Galoob, got bought out by Hasbro and they didn't really care to do anything with it. (though developed by UK company CodeMasters, I can't recall hearing if they released it in Europe. I imagine yes, though if it was, I'm surprised there doesn't seem to have a SMS version of the GG. The market would've still be high enough there for one. Not so in the US, especially after Nintendo delayed its release with a lawsuit.)
Now, the other device Action Replay got sold under different names.
There were things later, and today things calling themselves game genie as well. https://www.gamerevolution.com/review/351109-game-genie-review-bringing-modern-controller-xbox-one-ps4-switchhttp://thegamegenie.com/nintendo-ds/
Certainly the other brands had a far more storied history in the times post 16 bit era but game genie, official or otherwise, was not static either.
Equally it was not really Nintendo that delayed it -- Galoob filed for a declaratory judgement before release. Granted one could quite justifiably say given how well known Nintendo's heavy handedness in such matters was that it made that a smart move despite similar things existing on far older devices (such a mindset persists to this day https://www.gdcvault.com/play/1023470/-It-s-Just-Emulation
, and might as well have the follow up while linking things https://www.gdcvault.com/play/1025782/It-s-Still-Emulation-Saving
Could the custom rom be in between the cart and the console like a game genie?
September 07, 2020, 04:09:56 pm - (Auto Merged - Double Posts are not allowed before 7 days.)
Am I the only one that noticed what just happened?
Seems like a bot was all in this page with those reads jump then stop so quick. Very strange
I don't know if views are updated in real time. Quite often forum software, blogs and the like will run an update once every hour or so and adjust numbers accordingly rather than hammering the server all the time for what is not so fundamental aspects of forum running (replies matter, PMs matter, up to the millisecond view counts less so).
As far as custom rom being between the cart and console... yeah you are basically recreating a flash cart there, one with a ROM dumper attached. Some of the region adapters for the N64 did something maybe kind of like that (took mine apart once and it had a very fast, for the time at least, CPLD I think it was and presumably read the correct CIC from the donor cart on the back and then put it to the front). That are you are recreating the game genie concept which is almost a proto flash cart (indeed I might even make one in the modern world where it dumps the ROM to a RAM chip, not like SNES games are huge in size relative to modern RAM chips, and operate everything from there if I was going to make such a device today).
I could see some programmable chip being able to intercept all data reads, determine if one is in the proper range and then returning that particular mod for that particular read, otherwise passing all commands through as per usual. Whether an arduino in basic sketches would be it I am rather more dubious about -- the delays as it calculates things in basic sketches make all sorts of trouble even for LED displays that humans watch, doing that for something as quick fire and latency sensitive as cart reads... I am wary.
As far as writing memory to games. That is basic cheat making really and while the extremes get quite far advanced it is otherwise generally many people's first real introduction to ROM hacking related subjects as far as doing them (many will encounter trainers, translations and whatnot but that is using rather than doing). For things like the DS where the binary is loaded into RAM, as are files in general but that gets more tricky, you can alter the binary and do things as potent as a game genie in classical times*. Doing that from a controller would be a real feat but the general principle is nothing too drastic.
*more for others reading along at home. Action replay/gameshark/goldfinger/codebreaker/... are generally variations on the theme of RAM cheats. Good for making infinite items, adding things to inventories and such things that fall directly from data in RAM. Game genies in classical sense however alter what the ROM appears as. This can then alter fundamental aspects of how the game works (you don't just have infinite lives, you don't even react to being hit sort of thing). They are however far harder to make hence there being fewer of them out in the world. Being alterations to the ROM they are also more easily patched in directly where RAM codes are harder and tend to be reserved for individual hacks by skilled people or later devices that are either simpler or have more space and ability to have code added in (GBA and DS having such things, though the N64 kind of has something now).