Using the OSCR (Flash Boards)
NOTE: This only works for the Advanced Flash cartridges. It will not work for the UV cartridges. This will also require you 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 V15.0, which was released on June 30, 2025.
You need to enable the Flash options in the Config.h file of the Arduino code when you program your OSCR. As of release V15.0, these are found at line 184, 191, and 192.
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.
Note: If you get a compiler error, you may need to disable other modules that are currently enabled that you aren't using. For me, I was getting "content mismatch" errors until I disabled one extra module (I disabled the Master System module).
Make sure in your Cart_Reader folder, the Mega Drive .ino file is the most up-to-date at this link: https://github.com/sanni/cartreader/blob/master/Cart_Reader/MD.ino
At the time of writing (8/20/2025) the latest release does not include the latest version of this file.
Now, compile and upload the Cart_reader file to your OSCR.
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 file saved on your PC, 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.
Make sure your board is in the correct configuration for the game you want to make, which for this board is just making sure the jumper for the ROM size is set correctly. Then place your cart (with a shell, ideally) in the slot.
On the OSCR, navigate to Mega Drive/Genesis > Flash CFI. The OSCR will read the game loaded on the board (if there is one already flashed), then prompt you to select the new file to flash. Navigate to where you saved the ROM file, and flash 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.
If you have save data you want to load onto the cartridge, navigate to Mega Drive/Genesis > Game Cartridge > Write Save, then select the location you have the save data stored.