m5329 was unable to recognize a mass storage device, /dev/uba1 doesn't exist

Hi: I plugged an usb device, a mass storage device. the m5329 was able to
detect the usb device, but i can't mount the device using mount -v vfat
/dev/uba1 /mnt because /dev/uba1 don't exist how can I solve this?, I tried
to use mknode  /dev/uba1 b 125 0 but it didn't work.
Thanks a lot.
Bruno.

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Bruno Rodrigues Nunes
Engenharia Elétrica - UNICAMP