The SD reader (and shoulder buttons) are on one flex cable. It is not the cheapest but also not an extremely expensive spare part. The repair is fairly easy. have a look at ifixit.comI got a special case for y'all. Excuse me if J sound like a noob cos it's been really long and I'm not up to date. About a year or 2 ago, i had installed unlaunch, hiyacfw and Twilight menu using the flipnote glitch on my ndsi xl. It's firmware is 1.4.5u. I played on it for a few months, but the sd card broke inside it and in panic i ended up making it worse by damaging the sd card slot, trying to get it out. So now, the dsi has got unlaunch in it but everything in the sd card is gone and I can't get a new one. I would like to continue using it, so i decided to buy one of those xxx in one flash card. The seller doesn't provide any info about the flash card except the games. Since its on ebay, it can be returned. Hence I would like to try. Will it work on my dsi?
Using the internal SD with unlaunch, TWilight Menu++/nds-bootstrap has the benefit of allowing DSiWare and DSi mode for other games.
Those "Three-digit number in 1" carts are new enough to work on latest DSi/3DS firmware – shouldn't be an issue. You might want to backup the flashcart kernel (usually the µSD is taped in). I'm not a fan of those because a) it is commercial piracy and b) you never know what you get. Probably the lowest end (cheapest) flashcarts.
Good luck and have fun!