Where do Nintendo ROMs (GBC/GBA) come from?

I was wondering, who created the ROMs for GBA and GBC emulators? Are they "converted" from the actual games or are they created from scratch trying to recreate the game? I think the first one, otherwise it would be insane.. And if it's the first one, who could do that? Some engineers inside Nintendo or just some random dude?
P.S.: I'm not interested in a guide or how-to, just a general information to understand the situation.
Best Answer
The information will be kept general and unlinked here for obvious reasons, but there are pieces of equipment that can accept a GBA cartridge, and then connect to a PC. That would allow read access to a cartridge, and depending on the cart you can write to some as well. You might imagine it a bit like an SD card reader, except cartridges only contain one large blob of data, not any filesystem or such. ROMs are usually just dumps of the cartridge contents to disk using such a device, but it is also possible to write and compile your own, and with a "blank" cart to write to you can use one to test and develop your own games for the GBA as well.
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What is GBC GBA?
Game Boy and Game Boy Color were the handheld consoles that started it all. Their release showed that you could have well-made games that fit in your pocket. Handheld game consoles have evolved a lot since then, but there are many who still enjoy the classics.When was the GBA discontinued?
Game Boy AdvanceIndigo Game Boy AdvanceDiscontinuedJP: Q4 2006 PAL: Q4 2008 NA: Q1 2008Units sold81.51 million (as of June 30, 2010)MediaGame Boy Game Pak Game Boy Color Game Pak Game Boy Advance Game PakCPUARM7TDMI @ 16.78 MHz, Sharp LR35902 (8080-derived) @ 8.388 or 4.194 MHz19 more rowsCan you play Game Boy Color games on original Gameboy?
Original Game Boy Games will work on Game Boy, Game Boy Pocket, Game Boy Color, Game Boy Advance and Game Boy Advance SP systems. They will not work on the DS, DS Lite, or DSi. Game Boy Color Games will work on Game Boy Color, Game Boy Advance and Game Boy Advance SP systems.Was the Gameboy more powerful than the NES?
NES has a 1.7~ MHz processor with a 5~ MHz PPU, while on the other hand, the Gameboy has a 4.1~ MHz processor. Although the Gameboy seems better, they do not mention that the PPU of the Gameboy is actually only 1.05 MHz PPU. This is almost five times less than the NES!NEVER Buy A GameBoy Game Again
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Answer 2
I have seen videos on Youtube of people who make custom ports of games for cartridge based media. In this case it was called an eprom chip inside the bare cartridges that the person would remove and read/write to this chip itself. I would presume a similar chip may be found inside Gameboy carts and making a dump of such chip may be one way that a ROM could be created.
This could also in theory explain why flashcarts are able to function presuming they are primarily redirecting and redistributing data which would otherwise be located at this storage media chip to an externally mounted sd card.
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