The only difference between an SDHC and an SDXC is that SDXC runs the exFAT file system, whereas SDHC runs FAT32. Windows tries to prevent you from formatting any SDXC card into FAT32, so you have to use a special tool called fat32format to do the job, which is downloadable here FAT32Format.zip 1.Extract fat32format to somewhere easily accessible, such as the C:. 2.Connect your Micro SDXC card to your computer with an USB adapter. You should not need a special adapter, most SDHC ones will work fine. 3. Open a command line in admin mode. You can do this by going to start, typing cmd, then pushing ctrl + shift + enter. A UAC popup will ask if you want to run it, click yes. 4. Type CD /D C:\ or CD /D e.g. so if you put it in E:\folder1 type CD /D E:\folder1. 5. Type fat32format so if your SDXC is your F: drive type fat32format f: 6.(beware, this will erase all data on the sdxc card, so backup beforehand if needed) Push y then enter when it ask you if you really want to format. 6a. If it says something else is accessing the sdxc card, download process explorer Process Explorer run it, push ctrl + F, type in the drive of the SDXC card so in this example F: and push enter. It will show you what processes are accessing your SDXC card. Close them out and retry step 6. It should look like this when it runs successfully. 7. Congrats, your SDXC card will now work on your SDHC flashcart/devices. Now install the firmware needed for your flashcard and put the NDS files of your choice on it and try it out. Enjoy!! This has been confirmed to work so far on supercard DSTWO, EZ Vi, R4i Gold Plus and R4i Gold 3DS. There is no reason it should not work on any SDHC compliant flash card.