I've played around with flash carts for the DS and had great success so far. I'll detail the items I've tried and the results I've had.
I've tried 2 carts:
- R4i-Gold 3DS Upgrade Revolution MicroSD/TF Multimedia Flash Cart For 3DS/NDSill/NDSi/NDSiXL/NDS
- R4i GOLD Upgrade Revolution MicroSD/TF Multimedia Flash Cart For 3DS/NDSiXL/NDSi/NDSL/NDS(Support for 3DS V2.2 NDSi V1.4.3)
The carts themselves weren't actually original R4 carts. As I understand it, there are tons of cheap knock-off carts marketed as "R4" out there. Since I didn't have a DS and just wanted to play around with it, I decided I'd take the risk on the cheaper knock-off. I've been quite pleased with performance of the carts I've tried.
You can find more information on all the different cart types here.
I've tried some knock-off R4 carts ordered here. They aren't the fastest shipping (they all come from China); The first arrived in about 7 business days and the second order took over a month (3 weeks, then Chinese New Year further delayed). The good news about the slow order was that they gave me double what I ordered, though it may have been a mistake. I've been pleased with them overall, especially their prices, and would recommend them.
These carts don't come ready to go. There are some steps you need to take before you can pop them into your DS and use them.
- Get a micro-SDHC card
- This holds all of the software you'll be running on the cart. The cart itself only has the hardware to allow access to the DS itself.
- I'd suggest an 8GB or 16GB card if you plan on putting games on it. This will allow you to load it up and not have to deal with it often (or perhaps ever).
- Download Cart Software
- You'll find everything you need at the 'download' link of the website printed on your card (see references for examples)
- Simply read the description or look at the picture to find your matching product and download the corresponding kernel/firmware
- After downloading, extract the archive to the root of your SD card.
- Download Everything Else
- Now you can download homebrew programs and games written for the DS, as well as game ROMs, mp3s, videos, etc!
If you get a cart which advertises that it should work with your DS version and it just goes to a black screen when you try to launch it, you need to upgrade your cart.
- Go to the website for your cart.
- Find a 'upgrade firmware' link and download it
- Put the contents of the downloaded zip file on your SD card
- Put the SD card in your cart and into an old DS
- This is the annoying part...you need another DS which still works with your cart in order to update
- Turn on the DS and go the the games menu
- There should be a "game" called update, or maybe a version number, run it.
- This may take up to ten minutes to complete updating. Once it finishes, you are done!
You can find a list of many homebrew applications here.
- NOTE: many walk-throughs will tell you to 'Patch' or 'DLDI' games/homebrew before putting it on your cart. This isn't necessary on most new carts, including the ones I've listed here.
The most fun homebrew I've found is emulators for older systems. Here are a few:
- JEnesisDS is a Genesis/MasterDrive emulator which seems to work very well.
- Simply put your .gen files anywhere on your SD card (I used root/genesis) and navigate to them from the app.
- NesDS is an NES emulator which works very well.
- App in apps folder, roms in root/nes
- SNEmulDS is a SNES emulator which I haven't gotten to work properly yet.
- config file must be in root and roms in root/SNES
- Doesn't work with all games:
- Works: Super Metroid, Actraiser, Aladdin, Breath of Fire 1/2, Earthbound, Final Fantasy 3, Legend of Zelda - A Link to the Past, Super Castlevania IV
- Fails: Super Mario RPG, Actraiser 2, Starfox, Super Mario Kart
- Maybe: Donkey Kong Country 1/2/3 (some graphical bugs)
- S8DS is a Sega Master System emulator which is supposed to be very good.
- PicoDriveDS is an alternative Genesis/MD emulator I haven't tried.
- Lameboy is a GameBoy/GameBoy Color emulator which I haven't tried.
- NeoDS is a NeoGeo emulator I haven't tried.
If you wanted to find some games these appear to be your best bets. Please note that homebrew is usually legal to download and use (check licenses) and commercial game roms aren't.
- ds-roms appears to use Torrents for downloads. Has a large homebrew section!
- rom-freaks appears to use direct downloads. Has some homebrew.