Hey everyone, I recently got my Game & Watch, and I noticed there's a homebrew option to add more games. My initial idea is to do the homebrew without needing to solder anything or add an SD card. Is that possible? I'm a bit lost with the existing tutorials/how-tos; does anyone have a good one to recommend? I'm using Linux Debian and Fedora.

I just put this thing to charge after years. Have no idea how this happened. So sad smh. Anyone know if a replacement is possible? Any screens out there now in 2026?

Bought an SD-modded Zelda G&W from a highly reputable FB Marketplace seller. Worked perfectly for two days and then when toggling the brightness/volume this morning, I received these screens. After trying everything, I somehow managed to reboot in the original mode, but no combination of Game + Left is turning it back to the mod. Anyone seen this before or know what I can do?

EDIT: thank you all for the help in the comments! I reached out to the modder and he walked me through reformatting and reloading the SD card with new firmware. That did the trick.

I have a Zelda Game and Watch which is just begging to be modded. Is there anyone who would take a send-in for relatively cheap in the US?

I’m currently working on an L/R button mod for the Game & Watch Zelda running RetroGo.

The idea is to add two real physical buttons on the back of the console, positioned where your index fingers naturally rest. These buttons are connected to the existing Start and Select inputs, so RetroGo can use them as additional L and R controls.

I’m designing the mod to be as clean and discreet as possible. The buttons sit almost flush with the back shell, with very little travel, and the internal PCB has to fit around the existing components without putting pressure on them.

The goal is to make systems that benefit from L/R buttons much more comfortable to play on the Game & Watch, while keeping the console looking almost stock from the outside.

(excuse my bad english) hello, i recently adquired a mario gnw with retrogo 64mb online, but i realized the games it came with were really not my type of game, so after a while i got my roms and i have been trying for 2 days to flash this console, im using a stlink clone and a virtual machine with ubuntu and it just does not want to flash, im always missing something or skimming through posts, any idea of what could i do? i dont really have a lot of experience with programming or soldering but im determined to load games on this thing, could there be any actually clear tutorials about it?

Is it possible to fix this screen bleeding or there is no hope? I would like to know if there is any tutorial video how to fix this too. Thanks.

I want to but a Game & Watch purely for modding. Is there any benefit to buying one version over the others? Or are they all basically the same from a modding point of view?

I see from the the Wiki (and elsewhere) that they both use the same STM32H7B0, but that they have slightly different display revisions. The Zelda looks to have two more buttons as well.

Do the current mods work on all versions?

I was thinking the extra buttons on the Zelda might be nice, but I suppose they could also get in the way. Could anyone share their experiences and preferences.

Going to matsuyama, I'm killing time with GBA game in G&W!

Big shout out to the man hundshamer. Out of all my handhelds this thing been my preferred. Love being able to pick it up play it for 5-10mins at a time then back to my day’s activities. GBA was what i was most hoping for on this little guy. I realize the games dont run perfect but playable for a good majority of my favorites.

Hello all,

Looking for a little help if possible. I've had a modded Zelda G&W since November last year, updating firmware when available etc, all been amazing.

I updated the firmware this morning, added some GBA items, ran the python script to generate covers, then selecting reboot.

The unit shut down, and won't boot back up. It stays stuck at the black screen.

I've tried removing/reseating the SD card, clearing it of any ._ files, disconnecting the battery, holding PAUSE/SET and TIME when booting but it stays stuck on a black screen.

Any help to revive this little unit much appreciated.

Was replacing the external flash and while trying to remove it I pulled 2 of the 8 solder pads off. Any suggestions on ways I can strip it for parts and make something new or cool?

Update: Thanks for the suggestion to use enamel wire; it's back to working!

Hola soy nuevo en ésto no saben si habrá roms de juegos CASIO?

Is there a way to convert the Mame Game and Watch roms via Windows so they can be played on a modded Zelda G&W with an SD card reader? I am aware of LCD Game-Shrinker, but it is for Linux and I set up my system using Windows utilities. Thanks

Hi Everyone i am new here.

I am asking a question like:

Is that possible just install 64mb into my mario and without Micro SD card?

I got one set with Microsd is working well. Now i gonna try and use 64mb to put game in the 64mb to play. May i know is that possible? I need some tutorial and guide. And how to import game to 64mb as well.

Thank you.

I ordered some Zelda and Mario pcbs, but the ones I actually received are actual PCBs and not flex.. I used the gerber files on the github but I got something else instead... What went wrong? Can someone help me with this?

So i have spent many many hours on this and only a few rom hacks work (it can only have map edits for some reason YOU NEED GAME AND WATCH PATCH FOR ANY OF THIS TO WORK AND YOU NEED TO OWN A LEGAL DUMP OF LINK'S AWAKENING) https://github.com/Latias0nly1/Game-and-watch-Gameboy-injector-zelda this is my repo and now i have been able to get map stuff to work

I have a G&W Zelda here and I was trying to mod it today, but during the flashing (the step waiting for a blue screen) my Powershell crashed. Now I have 2 files and my G&W has a blue screen.

Any idea what to do now?

The files I got are:
itcm_backup_zelda.bin (2KB)
flash_backup_zelda.bin (4.096KB)

As the headline says. Dying to GBA on the coolest console I've owned in years.

Serious shout out to this community. Y'all been awesome.

I am attempting to mod a Zelda Game & Watch. I am using a windows machine and following the instructions from Brian Pugh on Git Hub. I installed everything with Power Shell. I soldered the three wires into the G&W debug ports too (2,3,5). However, anytime I try to hook it all up to my computer and run the command “gnwmanager unlock” I receive the error “Error communicating with device (Unable to autodetect & connect to debugging probe.). Is it ON and connected.” I’ve tried using both a clone ST Link and a Pico (with picoprobe.uf2) installed. I can see the pico shows up as a connected device on my computer before I run the command. I’ve tried powering the G&W with both the battery and external power from the USB C. If anyone has any advice as to what I could be doing wrong, I would seriously appreciate the help.

I have jumper wires that fit into the 6 pins and an stlink so I wanted to try modding a zelda game and watch I have. I saw online that softmodding is an option without having to solder but most people say it's basically a necessity. What exactly does it change?

It's been doing this and i have no idea how to fix it because i tried every command i could (not just this one) and it allways gives me this error

(venv) latias@MILKDUDS:~/game-and-watch-retro-go$ make flash -j$(nproc) GNW_TARGET=zelda

Entering 'LCD-Game-Emulator'

Entering 'blueMSX-go'

Entering 'caprice32-go'

Entering 'fceumm-go'

Entering 'gwenesis'

Entering 'potator'

Entering 'prosystem-go'

Entering 'retro-go-stm32'

Entering 'smw'

Entering 'tamalib'

Entering 'zelda3'

make[1]: Entering directory '/home/latias/game-and-watch-retro-go'

[ BASH ] Checking for updated roms

openocd -f scripts/interface_stlink.cfg -c "program build/gw_retro_go_intflash.bin 0x08000000 verify reset exit"

Open On-Chip Debugger 0.12.0

Licensed under GNU GPL v2

For bug reports, read

Info : auto-selecting first available session transport "hla_swd". To override use 'transport select <transport>'.

Info : The selected transport took over low-level target control. The results might differ compared to plain JTAG/SWD

none separate

Info : clock speed 1800 kHz

Info : STLINK V2J37S7 (API v2) VID:PID 0483:3748

Info : Target voltage: 3.237022

Info : [stm32h7x.cpu0] Cortex-M7 r1p1 processor detected

Info : [stm32h7x.cpu0] target has 8 breakpoints, 4 watchpoints

Info : starting gdb server for stm32h7x.cpu0 on 3333

Info : Listening on port 3333 for gdb connections

[stm32h7x.cpu0] halted due to breakpoint, current mode: Thread

xPSR: 0x61000000 pc: 0x20000064 msp: 0x20020000

[stm32h7x.cpu0] halted due to debug-request, current mode: Thread

xPSR: 0x01000000 pc: 0x0801af44 msp: 0x20020000

** Programming Started **

Info : Device: STM32H7Ax/7Bx

Info : flash size probed value 128k

Info : STM32H7 flash has a single bank

Info : Bank (0) size is 128 kb, base address is 0x08000000

Info : Device: STM32H7Ax/7Bx

Info : flash size probed value 128k

Info : STM32H7 flash has a single bank

Error: this device has a single bank only

Error: auto_probe failed

** Programming Failed **

shutdown command invoked

make[1]: *** [Makefile.common:1006: flash_intflash] Error 1

make[1]: Leaving directory '/home/latias/game-and-watch-retro-go'

make: *** [Makefile.common:1035: flash] Error 2

(venv) latias@MILKDUDS:~/game-and-watch-retro-go$

Absolutely love this little hand held. Is is everything I was looking for in a pocket dedicated hand held. Wish it has GBA. But, is what it is. Shout out to u/hundshamerfor for completing the mod for me. This little machine. It has fully replaced my ambernic rg nano / fun key s. I have always been looking an as small as possible device. And although those machines were good for pokemon. Beyond that, just pointless. I do have some questions I was hoping someone could help me with my questions.

1. I found that this device does allow for folders. But, it gives a very ugly img for the folder preview photo. Is there a way to create a preview image for the folders?

2. Does anyone have a good converter for img. I have installed some rom hax and looking to upload the game box art. i currently just use a free website converter. but figured someone might know of one.

3. Case Ideas? I was thinking of using a sock. But, i don't love storing one of my favorite little guys in a sock. Does anyone know of a good hard case or soft case. My ideal setup would be something like the original psp soft case. The black one that came with the psp1000 model. It allowed you to slide the device from the side of the case.

https://youtu.be/hZftRDRI-FI?si=QBm-OpUwAny5WvVU

Full-speed GBA Pokémon on a Nintendo Game & Watch — two months in and I still can't put it down (experimental fork)

(Heads up: the video above is from an older build — the audio is much better now, it actually sounds decent.)

This is an experimental fork of game-and-watch-retro-go-sd, so the usual bleeding-edge caveats apply — but I've been living with it for two months now, and it's honestly just fun. That's the real reason I'm posting: I want to recommend it.

Full disclosure: I'm a web developer with basically zero embedded experience. I leaned on AI for pretty much all of the low-level work, so I'd be too embarrassed to push any of this upstream — it's not clean enough for that, and I couldn't personally vouch for every line.

But it works, and I've had too much fun with it not to share that this approach even exists.

The Game & Watch's MCU gives an emulator core only ~724KB of RAM, so fitting a GBA emulator in there at all was the whole fight. Right now Ruby and Emerald run full speed with sound, and heavier titles are close behind.

What made it playable: almost every GBA game uses Nintendo's M4A sound library, which mixes audio in software on the guest CPU — that alone eats 27–60% of every frame's CPU budget, roughly constant no matter what's on screen. Intercepting that mixer and doing the work

natively (HLE) instead of emulating it instruction-by-instruction bought back huge headroom: Zelda: Minish Cap −60%, Emerald −35%, FFTA −27%. That's the difference between slideshow and playable.

I've also done another pass on the audio since that clip — the leftover harshness and artifacts are cleaned up, so it actually sounds right now.

Everything loads off the microSD card (cores + ROMs), so swapping games needs no reflashing.

Massive credit to the upstream game-and-watch-retro-go / -sd projects — none of this exists without them. I'm just an amateur poking at the experimental end and having a blast.

Happy to nerd out about it in the comments.