I own a Wii U and a Samsung 64GB SDXC microSD card. Achieved so far: -formatted to fat32 from exfat -Running Homebrew Channel + Wii Flow -Wii Menu Reports Blocks Open of 409456+ (this is greater than a 32GB Card reports, so success... the wii is seeing the space! -Have successfully run wii backup from wbfs file on the SDXC card using WiiFlow Here is the quick guide: Step 1: get a SDXC card and Place it in a windows PC with a card reader that supports SDXC Step 2: Grab this utility: http://www.ridgecrop.demon.co.uk/index.htm?guiformat.htm Use the utility to format to Fat32, you basically just do a quick format using default settings. (Don't try to format a SDXC card to fat32 using windows... it wont work. YOU NEED THIS TOOL) Step 3: Copy over your apps and homebrew files, etc... whatever you want to run. Then place it into your Wii U. I couldn't get USB Loader GX to load isos from the SDXC card, but I'm not very familiar with the process for getting usb loader GX to load ANY isos from sd card before. Wii flow worked just fine for playing back wbfs game backups. Still to be tested: Need to test one of those 128GB SDXC cards.... my guess is that it will probably work though... Will be nice once I have one of these installed, can run plenty of game backups off a 128GB and no external drive needed! Also need clarification on getting this to work on USB Loader GX, I don't think it is a SDXC problem provided it is converted to FAT32 correctly.