illmasaki said:4 gigs is to big? lame they shouldnt put a capacity limit on it
It's the limitation of FAT16 that is used by many products that use SD cards. Until a couple months ago, SD cards bigger than 2GB were not popular at all.
For more information, see:
http://www.microsoft.com/technet/prodtechnol/windows2000serv/reskit/core/fncc_fil_blpd.mspx?mfr=true
At some point, Nintendo can release a firmware update to allow the use of FAT32.