I recently bought a 64gb flash drive for my f700 bt, unfortunately despite working on my computer great my hu wont read the usb at all. I then bought a 4gb run of the mill flash drive and it works great. I noticed my 64gb flashdrive is in the exfat format type where as the 4gb is in the fat32. are our units compatible with exfat? Also I bought a external harddrive laptop style that gets power from the usb. My unit also doesnt read that, and i think it may be a similar problem. Any advice would be great thanks