Seagate (post-2020), LaCie, ADATA, and any USB 3.2 Gen 2 drive.
Verified to work perfectly out of the box when formatted to FAT32. usb loader gx usb compatibility list
Standard 2.5" mechanical hard drives often require more than the 500mA a single Wii USB port provides. A USB Y-cable draws power from both ports to ensure the drive doesn't crash during gameplay. Summary Checklist for a Working Setup Drive Type: Portable HDD or SSD (Avoid cheap flash drives). Format: FAT32 with 32KB clusters. Table: MBR (not GPT). Software: d2x cIOS installed to slots 249/250. Seagate (post-2020), LaCie, ADATA, and any USB 3