If you must use a flash drive, stick to these specific models. Note that 128GB+ flash drives frequently cause more issues than smaller capacities USB Devices Compatibility List - WikiTemp, the GBAtemp wiki

Avoid these or prepare for troubleshooting (freezes, slow loading, or non-recognition): : Reported to fail loading into the app entirely. Intenso 4GB : Often causes black screens when launching a game. SanDisk Ultra Fit 128GB : High failure rate due to capacity/controller issues. Unbranded/Generic

: Frequently cited as a budget-friendly, reliable choice specifically for Wii homebrew. Known Incompatible / Problematic