For software bigger than 2M, one must connect (with solder blob, 0K resistor, etc) the >2MB part of the jumper for smaller or equal to 2MB software, one must do the same with the <2MB part of the jumper. You only need to solder 3 or 4 wires and the adapter board to an old cartridge, PCB adapter boards are manufactured on OSH park to ensure the best quality of castellations. This jumper is necessary for software bigger or smaller than 2MB to correctly save and detect the FeRAM. Flash Memory Adapter for some Game Boy Cartridges. JP1 jumper: This jumper is the result of some tests with varied sized Save RAM suporting software. One may join how many ROMs he wants to, just be shure that the result file is smaller than the total size of the EPROM and that the ROMs fit correctly to each desired bank to make software switching possible. How to make multirom file: Just use the CMD command 'copy /b rom_x.bin + rom_y.bin + rom_z.bin rom_result.bin' to join them to one file. This technique may not be compatible with save supporting Genesis software. ROM_y begin at 0x180000 -> Switch A19 and A18 off Save support for all ROM sizes (Selection for Switch just A19 off (pull-up).In the actual state, this cartridge features: It was developed in KiCAD and tested in real hardware. This projects uses a 27C322 4MB EPROM Chip and a FM1808 32KB FeRAM as save storage. A open Sega Genesis cartridge PCB with save feature
