I believe the pins are on the PCB to the right of the chip in the screenshot, but it looks like he left the headers soldered off.. Atmel programers are pretty cheap as well fwiw.

Thanks for the info. I'll probably put it off for now, though. That's a little more involved than I have time for right now. I mean, it works well enough right now, so no urgent need to upgrade.

Oh yeah, I was mistaken. I thought the capacitors next to the atmega was an ftdi header. The atmega is socketed though, so if you have an arduino with that same chip you should be able to pop it out and put it in the arduino to reprogram it. Or maybe you could just ask xiwi?

I think I might be out of luck. You can see the PCB here and this is a photo of what I could get without taking off the top.

You might have to open the case up, and look either for some pins or unsoldered holes that match this kinda of cable:
https://www.sparkfun.com/products/9718

If you post a pic of the pcb we can probably point it out for you.

It looks like there is a header on the PCB for a programmer. You need a FTDI usb to serial adapter (you can get them on ebay for a few bucks) and then you will be able to program it. Or just get someone else to do it for you!

It is one of the newer models and I don't see any FTDI port. The only places to plug anything in are the Midi In, Out, Link, and 9v.

My xiwi had a FTDI port, did he remove it in later versions?

Yeah... it is a Xiwi and there is no USB port on it.

You need to plug it in via usb to your computer, then use the arduino IDE to upload the new code.

EDIT: Like not the midi cable, but the actual usb jack on the arduino (assuming it has one).

If you bought it from me, I have added some things (like for the PS/2 jack), so you'll want to use my build.

On a related note, how would I update my existing arduinoboy to the most recent code release? I have a midi-usb cable.

The only other thing I can think of is start+select+A (I think) turns the display off. Theoretically this could help mGB perform better, but honestly I'd be a bit surprised if it did much (chime in if I'm wrong). Pressing B will reset all your presets.

I am kind of working on a little instruction manual, but we'll see if that ever gets finished.

Thanks for the kind words!

Ok! Thanks for clearing that up. I was thinking about emailing you directly but I happened to stumble on to this thread and here you are! Is there any documentation that goes along with mgb? I mean, it's pretty self explanitory but I'm new to the gameboy as an instrument. Didn't know if there was anything to know besides what's on the screen.

Great product by the way!

Yep, that's correct. Again, the first two channels (PU1 and PU2) can only make square waves. So to have all the sounds the same, channel 3 (WAV) must be set to a square wave.

Ok, so it's only poly with square wave? The issue I'm experiencing isn't an issue - mgb is working as intended?