No on the normal ARDSi without microSD Slot isnt any Storage for homebrew, but with an tool of blasty you can rewrite the flash of the ARDSi, if you know enough about DS Programming, Reverse Engineering (rom hacking) then you could modify your ARDSi, and i think it's possible to solder an microSD Slot on your ARDSi and flash the right firmware for it on your ARDSi (on my old ARDS, there are solder pads for an microSD Slot, solderpads for an DS Slot Connector and on two sides are USB Connector solder pads (if you had an DS Slot Connector on your ARDS, you must solder the usb port on the other side of your ARDS)...
But if you like it simple, buy an homebrew friendly flashcart:
>R4 (if you run Wood)
>Acekard 2 (if you run Akaio)
>Supercard DSTWO (if you run wood with woodr4.plg, or EOS (i dont know how good EOS is, i'm using only MoonShell)
>Acekard RPG (if you run Wood)
>iSmart Premium (no guarantee)
Yes, i'm using mine DSTWO only for legal purposes, i'm using only homebrew...
Is there anyone which do only legal thing with his flashcard except me?