On dsi my r4 card comes up with an error - Nintendo DSi White Console

Hi Cagg,

This problem is likely because the latest Nintendo based firmware doesn't actually support old R4 and fake R4i cards, only very specific R4i cards support it (namely the official R4i 3DS). You can probably swap your R4 card for a newer card like the Acekard 2i, Supercard DSTWO, Cyclo DS iEvolution, or frankly any of a number of cards that will work on the new DSi XL and 3DS consoles. I would personally recommend the Supercard DSTWO, though, I use it myself. It also has GBA emulation built-in which is kind of awesome if you want to play older games. The Acekard 2i is cheaper, but doesn't have the GBA functionality.

I'm not sure where you're based but if you're in the US, use "dsmagazine" as a voucher (I found this on an online DS news site) for DSCardWorld.com, they're authorised retailers of the Acekard and Supercard - I think also a few others. NDS-gear.com is probably better if you live in the Europe or in the UK though since they have cheaper shipping there. They still stock authentic cards so you should be all right either way.

Good luck, and please kindly upvote my answer if you've found it useful! :-)