When the PicoZed FMC Carrier is configured for the USB 2.0 to be in Host mode, 500 mA should be available on Vbus for a device plugged in. Unfortunately, this is not the case for the PicoZed FMC Carrier. A NC7SZ66 bus switch is used in to deliver power to Vbus in Host mode which is only rated at 128mA. You may find that some USB Devices will not enumerate properly when plugged in. This could be due to the fact that there is not enough current available.
A work-around for this is to use a powered USB hub plugged into the PicoZed FMC Carrier USB 2.0 Host port.
This will be added to the PicoZed FMC Carrier errata in the near future.