Need sd card help

So I'm trying to use my little brothers 3ds to play Pokemon y because he doesn't play it anymore. and to trade online I guess you need an update so I go and try to download it but it says I don't have enough blocks to download it. so I go into the sd card and delete everything my little brother says is okay to delete. After that all that's left pretty much is saved data, but there still is only 170 blocks available. But it's a 4gb sd card so I don't understand how there's so little space? Can someone please help me to figure out what's going on.

What exactly did you delete? Are there still games and demos in the Software, Extra Data and DLC sections of your Data Management?

@ANIMEguy10034:

I think I just deleted some video thing and some app that he said he didn't know what it was

And there are still all the sections in the data management screen, but I think all that's left on the device is all the saved data for the games

@zchary21: How large are the saved data for the games? What's the size of the largest software? Do you remember how many blocks were available in your SD card before deleting the apps? Was it less than 170 blocks or did it stay at 170?

Was the SD card used for other purposes? Does it have a lot of music and videos?

Actually underneath the software option there isn't anything, I'm pretty sure that's where the saved games and stuff are suppose to go, but all the games still have all the saved data. There were about 80 or so blocks available before I deleted the two other things, which just makes it even more confusing. But I did just go into this dsi managemt thing and it says my system memory has 1000 open block, I don't know if this is just what it came with or something else.

@ANIMEguy10034:

there's no music or movies on it from what I can tell either

Since space did clear up a bit after deleting those two apps, then it's safe to say that the SD card is working normally. If there are no music or videos, then it has to be all the downloaded games, saved data, and possibly backup data taking up too much space.

The DSi system memory is separate from the 3DS SD card memory. It's the internal memory solely for DSiware games.

You're going to have to delete something else to make a bit more space for the Pokemon update or buy a larger SD card.