I use the same setup. It's very underrated.

Not sure if you're still working on this project, but I recommend just buying a FMB PS2 memory card from eBay. I think I got mine for $18 USD. It saves a lot of time and headache.

I have a Game Gear that's already half way through this mod. PM me if you're interested in buying.

Very good advice from bacteria!

I've also added a micro USB to my GBA SP. It was very simple compared to the GB Pocket because it's already setup to be rechargeable.

At first, I wanted the Pelican battery so I wouldn't need to cut any plastic on my SP, but I couldn't find any for purchase. The DSi battery looks very loose to me, but the DS Lite battery holds tight on its own. The electrical tape is only used as an insulator to prevent shorts. Once you have the b...

So, putting this inside a GB Pocket is really cool, but for practicality purposes, wouldn't an original GBA have worked better? It has shoulder buttons, meaning if you add extra face buttons like that other guy did you can play SNES games with the proper control scheme. Obviously not an issue if yo...

Searching Google, I found that people were putting DS and DSi batteries in GBA SPs to extend the battery life. Genius! The original GBA SP battery is 600mah and the DSi battery is 800mah to 1050mah. I already had a DS Lite battery on-hand and saw it was 2000mah, more than three times the capacity of...

This is a similar project with DMG Game Boy. It has the best design I've seen for this type of project. It also has added buttons for games needing more than the A and B buttons

https://www.youtube.com/watch?v=aMhTMgDHGaM

I just tried unplugging the game and that turned it off. It was still weird though; I didn't even think that that could happen! Obviously, if the LED is glowing, it has power. The only components besides the battery that retain power are capacitors. It could be that something is damaged or some log...

I painted my Game Boy Light as close as I could get to a DMG gray. The original gold color was worn and scratched and this brought new life to the unit. I couldn't do much to revive the old labels, though. Also, I added a usb rechargeable battery. Let me know what you think of it.