There’s only one thing the entire retrogaming community agrees on: the best experience comes from playing on original hardware. But even if you get your hands on a vintage console or handheld, you may end up resorting to emulation due to the cost and difficulty of building a physical game library. For this reason, there are different storage solutions for many consoles. They often allow you to copy game ROMs to an SD card that the console can access. But if you have a Nintendo Game Boy and want a hackable option, then Squareboi is the solution for you.
ALXCO-Hardware developed Squreboi to be “as accessible and user-friendly as possible”. Unlike most flash cartridges on the market which are closed source, Squareboi is an open source project that you can hack to your heart’s content. You can copy game ROMs to the device to play them on your Game Boy, Game Boy Color or Game Boy Advance. It stores game saves without requiring a battery and allows you to copy those game saves to your computer if you wish. It also doubles as a cartridge reader if you want to dump a ROM. The maximum storage space is 4MB ROM and 32KB RAM. It’s Arduino compatible, so you can modify the firmware if you want.
The Squareboi design uses a few different PCBs that you select based on your needs. To start, you will need at least the motherboard and the Writeboi programming card. You will need a JTAG programmer to flash the firmware and an Arduino Mega 2560 development board to connect the Writeboi board to your computer. There are optional daughterboards to add RAM or ROM if needed for the game/program you want to run, which is really useful if you are in the homebrew scene. A donor cartridge (aftermarket is fine) is required for the case.
Different boards require a handful of different chips for memory, but the chip that does the heavy lifting is a Microchip ATF1502ASL CPLD (complex programmable logic device). A CPLD is like a simple FPGAs and it eliminates the need for hard-to-find original ICs. Full fitting instructions are available at the Squareboi GitHub page.