5. What USB storage are supported via OTG by the X5?

A: Owing to some limitations of the controller board, the X5 currently only supports USB storage utilizing USB controllers from specific brands, specifically:  Skymedi, ITE, Innostor, SiliconGo, Phison, and CBM (Note: these are the brands for the USB controller not the brands of the USB storage device)
If you are not sure of what brand of controller your USB storage is using, you can download the PC utility (Identification tool for the main control chip of the U Flash Disk) for checking, and here is the link for download:
Click here.