Using the OSCR

Using the OSCR will require you to have finished assembling your cartridge before flashing will work.

Please visit the OSCR wiki for general instructions on how to set up and use the dumper. The following more specified instructions were written using release V14.3, which was released on August 16, 2024.

As of the time of writing (March 30, 2025) the only two mapper types flashable by the OSCR are MBC3 and MBC5.

Enable Flashrom Programmer in Arduino Code

You need to enable the "Flashrom Programmer for repro carts" options in the Config.h file of the Arduino code when you program your OSCR. As of release V14.3, this is found at line 185 and 186.

Just remove the "//" before each of these lines to enable them. Make sure the rest of the config options are correct, then upload them to your OSCR.

Step 1: Load ROM/Save onto SD Card (if Required)

If you have a ROM from a game you dumped with the OSCR, you won't have to do this step. But if you have a ROM file that you had to prepare, such as with a patch or ROM hack, you will need to load it onto your SD card for the OSCR. You can also take this opportunity to load any save file you have for the game onto the SD card as well, if you have one.

Once you've done so, put the SD card into the OSCR and turn it on.

Step 2: Finalize your Board

Make sure your board is in the correct configuration for the game you want to make - make sure the RAM size is correct, etc.

Step 3: Program the Game

On the OSCR, navigate to Game Boy > Flash Repro > GB CFI Repro.

Now, just navigate to where you saved your ROM file, and flash it to the board. It may take a while to program. If at any point the programming hangs at "Writing flash", your cart may not be placed in the socket properly, or you may have a soldering issue somewhere on your cartridge.

Step 4: Program the RAM (Optional)

If you have save data you want to load onto the cartridge, navigate to Game Boy > Game Boy (Color) > Write Save, then select the location you have the save data stored.