Knoxximus has found a method which allows 4GB SD cards (non-SDHC) to be fully utilized as a Wii storage card.
To quote: For the people who DON'T LIKE TO READ, THIS SOLUTION ALLOWS YOU TO USE AN OTHERWISE UNSUPPORTED SIZE SD CARD (4GB) TO ITS FULL POTENTIAL AND STILL HAVE VERY DECENT TRANSFER SPEEDS!
Okay! Now we all know that Nintendo's official line is that cards larger than 2GB will not work on the Wii...and for the most part this is true. However...what about a 4GB SD (NOT SDHC) card that PRETENDS it's a 2GB, but then over time can be slowly expanded to meet it's 4GB potential?
I scoured the net for info on how to get this to work, and now I present to you the fruits of my labor. Here is a mini FAQ on how to get 4GB SD cards to work on your Wii.
1st of all, get a hold of this non-SDHC SD card. Here is a link at http://www.newegg.com/Product/Product.aspx?Item=N82E16820208411 where it is $10.75.
OK! So you got your SD card. You'll notice that if you format it through Windows or your Disk Management, regardless if you do FAT/FAT16/FAT32, the Wii will NOT recognize it. No problem. Google and download an app called SDFormatter. Better yet, just use this http://gbatemp.net/index.php?download=389.
Okay, so now you format your SD with this program. It will take a LOT longer than a normal SD format. Don't panic!...it's normal. When this is done, if you were to insert the SD back into the Wii, it would at least display empty channels, which at least means it recognizes the card. However, you will not see a how many blocks remaining number, and the Wii will refuse to write data to it.
Bummer, right? No problem. Now the trick is to fool the Wii into thinking that your 4GB card is actually a 2 GB card.
1st, take your current Wii Card and make a copy of it on your computer. Then, drag that folder to the 4GB card to copy. Then go into my computer, right-click the SD card, select properties, and keep your eye on the free memory.
An empty 4GB card reads as 3.72 or so GB. In my case, after I copied my existing Wii data to it (544 MB), I had like 3.20 GB's of free space. If you were to insert the card now, you would SEE your Wii data, but would be unable in transfer anything to the SD from the Wii. You can only go one way...from the SD to the Wii.
Now comes the fun part. Your job is to get the free memory down to 1.99GB or lower... basically anything under 2.00GB. I accomplished this by using a 700 MB Naruto movie, 2 double episodes (298 MB and 285 MB) and a few odd episodes of Game Center CX which took me down to 1.99GB on the nose (took me some trial, error, and different sizes and genres of .AVI's to nail it). Doesn't matter what you use...apps, programs, porn....as long as it pads your card down to 1.99GB or lower, you're in business.
Note that whatever you use will be transparent, meaning that nobody would see your porn AVI's recognized as data. Just make sure that it's not one big azz file... I will explain why in a moment.
NOW put it in your Wii. You will now see something like this (pictured below).
As you might have noticed, the number of blocks will be greatly increased for the same amount of Wii data! What you DON'T see is that I have 2 1/2 more pages of games on this card. On my 2GB card, my total blocks remaining was 11108!
*Also, a blank, freshly formatted 2GB card weighs in at 15466 blocks available, which makes my case with the picture above that much more solid.*
NOW! Some of you are saying, "Well geez Knoxx! I might as well stick with my 2GB card if I can't even use the full 4GB's of space!" Valid point. Now here's why you shouldn't:
1) The speed gain for transfers is comparable, depending greatly on factors such as brand, read/write speed, and format.
2) As you slowly fill your SD with videogamey goodness, and as you get low on blocks, stick your card back into your PC and lose that 700MB Naruto movie. When you stick it back in the Wii, your remaining blocks would have magically increased and you still have all of your previous data!
Bottom line: As long as your card's free memory stays at 1.99GB or lower, you WILL be able to use MOST if not ALL of that 3.72 GB's of space. It takes a little bit of juggling, but I feel it is worth it.
Well....there you go! You're welcome!!
Disclaimer: Whenever you decide to remove a file to increase your space, save a copy of the card in it's current state on your computer, just in case. I can't guarantee that this method is infallible, but it has been working AWESOME for me thus far. And who knows....if this makes too much noise, Nintendo might try to squash it (though I highly doubt it).
EDIT: The increased transfer speed maybe due to my choice of card. The Transcend 133x 4GB SD card has a sustained read/write speed of 20/MBps, whereas my Sandisk Ultra II 2GB SD card (1st edition) has read/write speeds UP TO 10/9 MBps. Regardless, the extra speed goes nicely with the extra space.
Adjusted my initial times for the 2GB card based on a fresh format and possible stopwatch read error, as it is not digital. However, the other card is STILL much faster, though probably not because it is a 4GB, but because it has a higher rated read/write speed. Still, 4GB beats 2GB any day of the week.
Also added 2GB space in blocks info to main post. More PlayStation 3 News...