GBA Game Paks generally contain a ROM chip and a second chip used for saving data that persists over power-off.
Unlike Nintendo DS games, GBA games basically never have protection or encryption, but instead there is the issue with saves. There are three different save types on GBA, and flash cards only have one (usually SRAM) so the other two have to be emulated somehow. This can be done in hardware, or the ROMs can be patched to change their save type.
Nintendo's official code library for working with saves contains a string identifying the type of save hardware that a progran is designed to use. This is used during manufacturing to specify what kind of hardware is placed on the Game Pak board. Piracy tools use the version string to identify how to patch the ROM.
|Name||Sizes||Features||Game types||Example games|
|EEPROM||4kbit (0.5kByte) / 64kbit (8kByte)||The most common, over half the games use this, small, cheap||Simple level saving, high score keeping||Super Mario Advance, Tony Hawk's Pro Skater|
|SRAM||256kbit (32kByte)||The second most common, roughly a third use this, medium size, fast||More detailed level saving, state saving||F-Zero, Castlevania, MegaMan|
|FLASH||512kbit (64kByte) / 1024kbit (128kByte)||Rarest, biggest, slow||Big complicated RPGs, games with customization||Pokemon, Final Fantasy Tactics Advance|
- 4kbit or 64kbit regardless of version, ex. EEPROM_V122 can be both 4kbit and 64kbit. The only way to find the save size is to run the ROM in an emulator such as VisualBoyAdvance and look at the size of the .sav file.
- In commercial games, always 256kbit regardless of version. Some homebrew programs, especially emulators on GBA, use 512kbit SRAM, and so do FLASH games that have been patched to use SRAM.
- 512kbit or 1024kbit and the save size is in the version, ex. FLASH1M_V102 is 1024Kbit and FLASH512_V130 is 512Kbit. The earliest versions of flash saves didn't have the size in the version, but they are all 512kbit, ex. FLASH_V123.
- Seems to have replaced SRAM, it's typically found in cartridges made in 2002 and later. Behaves and functions just like SRAM but does not require a battery.