How to Flash GB/GBC Roms

Flashing a Game Boy (.gb) or Game Boy Color (.gbc) ROM to a blank flash cartridge requires careful consideration of the hardware and software involved. The following steps outline the process and key technical factors to ensure compatibility and functionality.

Requirements:

  • Flash Cartridge: A rewritable cartridge compatible with GB/GBC systems.
  • Flashing Hardware: A programmer such as GBxCart RW, Joey Jr., or similar. I personally use GBxCart for creating custom carts but any flasher hardware will work. If you are in US, you can purchase GBxCart from the following stores:
  • ROM File: A legally obtained GB or GBC game file.
  • Flashing Software: The utility provided by the hardware manufacturer (e.g., FlashGBX).

Key Considerations:

a. ROM: Most GB games typically range from 32 KB to 1 MB, but some GBC games can be up to 8 MB. Ensure the flash cartridge has sufficient storage capacity for the ROM.

b. RAM (Save Memory): RAM can be SRAM/FRAM/EEPROM. Verify that the flash cartridge supports the required RAM size and includes a functional battery if needed.

  • SRAM (Static Ram): The most common save type in original GB/GBC cartridges, but requires a battery to retain data when the console is off.
  • FRAM (Flash RAM): Non-volatile memory used in some modern flash carts for saves and retains data without power or battery.
  • EEPROM (Electrically Erasable Programmable ROM): Rare in GB/GBC era but used in some special cartridges. Non-volatile, no battery needed.

c. Mapper (Memory Bank Controller): Original cartridges use MBC chips such as MBC1, MBC2, MBC3, or MBC5. The flash cartridge must emulate the correct mapper for the game to function properly. Most modern flash cartridges support multiple MBC types, but confirm compatibility before flashing.

d. RTC (Real-Time Clock): Keeps track of the current time, even when the console is powered off. Here are the games that uses RTC:

  • Pokémon Gold, Silver, Crystal: Day/night cycles, time-based events.
  • Harvest Moon GBC: Seasonal changes.

If you need RTC option, we recommend this rewritable cartridge that should be compatible with the most GB/GBC games. This should work with most of the gb/gbc games including official pokemon releases and rom-hacks.

Flashing Procedure

  1. Connect the Flash Cartridge to the flashing hardware and then to your computer.
  2. Launch the Flashing Software and select the appropriate device.
  3. Erase the Cartridge Memory if required by the software.
  4. Load the ROM File into the flashing utility.
  5. Configure Settings: Select the correct mapper type based on the ROM header and enable save RAM if the game requires it.
  6. Initiate the Flashing Process and wait for completion.
  7. Verify the Flash (optional but recommended) to ensure data integrity.
  8. Safely Remove the Cartridge and test it on a GB or GBC console.

Will an MBC1 ROM run on a flash cart that uses MBC3?

Yes, in most cases. MBC3 is backward-compatible with MBC1 for the basic banking commands most games use. So if your flash cart is set to MBC3 mode and you load an MBC1 ROM (like Pokémon Red/Blue or Yellow), it usually works fine. This flash cart will work with most of the games that uses MBC1,3,5.