The Flash Boy: How to Dump, Back Up and Flash a Game Boy Cartridge

Somewhere inside almost every old Game Boy cartridge is a tiny coin battery, and it is slowly running down. When it finally dies it takes your save with it: the Pokemon team you raised for a hundred hours, the high scores, the ranking you fought for. The Flash Boy exists to get ahead of that moment. It is a small USB device that connects a Game Boy cartridge to a modern computer and lets you copy everything off it, the game and the save alike, before time does the copying for you. It can also do the reverse, writing a game onto a blank cartridge, though as we will see that last trick is the fussiest of the lot.

What the Flash Boy is

The unit in the collection is a Flash Boy made by Backlight Engineering Lab, a small maker that put the board in a clear acrylic case and labelled it, plainly, a cartridge flasher and dumper. The label is worth reading closely, because it tells you exactly what the device is for: it works as a dumper for original Nintendo DMG, CGB and MGB cartridges, meaning the original Game Boy, the Game Boy Color and the Game Boy Pocket, and as a flasher only for its own Flash Boy cartridges. In other words it will read almost anything, but it will write to only a narrow, specific set of carts. That distinction is the single most important thing to understand about it.

The little USB bridge between a thirty-year-old cartridge and a modern PC

The hardware itself is simple and honest. A single cartridge slot sits on top, a USB-B port on the side carries both power and data to the computer, and a small switch selects between 3.3 volts and 5 volts so the board can match the cartridge it is talking to. There are no drivers to fight with and nothing to configure on the device; all the intelligence lives in the software on the PC. It belongs to a long and well-understood family of homebrew cartridge tools rather than to any one commercial ecosystem, which is exactly why it is dependable once you know how to drive it.

What it can do

In practice the Flash Boy does four jobs. It can dump the ROM, reading the game itself and saving a perfect copy as a file on your computer. It can back up the save data, lifting the contents of that failing battery-backed memory onto the PC where it is safe from the dying battery. It can write a save back onto a cartridge, which is how you restore a backup or move a save from one cart to another. And it can flash a game onto a compatible blank cartridge, turning a rewritable cart into a working copy of whatever ROM you send it.

There is a lovely side effect of the save-backup feature. A Game Boy Camera keeps its photographs in exactly that battery-backed save memory, so backing up a Game Boy Camera cartridge captures the pictures too, ready to be opened in a separate photo viewer and rescued as ordinary image files. For a collector, though, the headline is the plain save rescue: a battery that has already died cannot be recovered, but a Flash Boy used in time turns a decades-old save into a file that will outlive the cartridge itself.

The software it needs

The board is only half of it; the Flash Boy is driven by a small Windows program called GameBoy Cart Flasher, usually shortened to GBCF. It is free, it has been around for many years, and it is the reference tool for this whole family of flashers. The workflow is straightforward: install the program, connect the Flash Boy over USB, insert a cartridge, open Cart Info to set or confirm the flash and RAM type for that cartridge, and then choose your action, backup ROM, backup save, write save, or write ROM. The device's 3.3 and 5 volt switch is set to suit the cartridge in the slot, and the manual that ships with the software explains the details.

One warning saves a lot of confusion. There is a completely different product also sold under the Flash Boy name, the Flash Boy Cyclone, which is a clone of the popular GBxCart RW reader and is driven by other software such as FlashGBX. That software is excellent, but it is meant for the Cyclone and GBxCart hardware, not for this Backlight board. If you own the Backlight Flash Boy, GameBoy Cart Flasher is the program you want; if you try to pair it with the wrong tool you will simply chase errors.

Which cartridges it reads

For reading and dumping, the Flash Boy is happy with the vast majority of original Game Boy and Game Boy Color cartridges, the Game Boy Pocket titles included, since they are all electrically the same family. Reading is the easy half of the job, because the device only has to make sense of what is already there: it walks through the cartridge's memory and copies it out. Backing up the ROM and lifting the save off a genuine Pokemon cartridge, a Zelda, a Tetris, is precisely the sort of everyday task it was built for, and it does it reliably.

Which cartridges it can write

Writing is where people are most often caught out, so it is worth being precise. You cannot flash an ordinary retail cartridge; a real Nintendo game is a fixed mask ROM and can only be read. Flashing needs a rewritable cartridge, and not just any rewritable cartridge. The Flash Boy and its GameBoy Cart Flasher software speak to a specific type of flash chip, the classic AMD-style parallel flash used in the original homebrew cart designs: the AM29F016 for a 2 megabyte cart and the AM29F032 for a 4 megabyte one, paired with a genuine Nintendo memory-bank controller chip such as an MBC1, MBC3 or MBC5. That combination, an AM29F flash plus a real MBC, is exactly what the maker's own Flash Boy cartridges use, and it is the only kind the board knows how to program.

Modern Flash Cartridges

This is where a very common misunderstanding lives. It is tempting to assume that any MBC5 cartridge from an online marketplace will flash, but MBC5 describes the mapper, the chip that handles memory banking, and says nothing about the flash chip underneath. Many inexpensive modern flash carts are built around a small programmable-logic chip, a CPLD such as an Altera EPM240, standing in for the mapper and driving a flash chip that expects a different programming sequence entirely. Those CPLD-based carts are made for the GBxCart RW and FlashGBX world, and the Flash Boy cannot write to them, even though it can usually still read a game that is already on one. If you want to flash your own games with the Flash Boy, look specifically for a cartridge built on an AM29F016 or AM29F032 with a real MBC, not a generic CPLD board.

Preservation, not piracy

A device that copies games sits in a grey area, and it is worth being honest about that. The same tool that rescues a dying save can also duplicate a game, which is why backup devices have always lived on the edge of what publishers were comfortable with. In a collection like this one the Flash Boy earns its place firmly on the preservation side of the line. Its real value is keeping the fragile parts of these cartridges alive, the saves and the data that no factory will ever press again, and letting a curator verify exactly what is on a cartridge without wearing out the original by playing it. It is a modern instrument built for an old and quiet problem: the slow ticking of a thirty-year-old battery.

To see the Flash Boy among the other backup and homebrew devices in the collection, come and explore the Game Boy Museum.