TQMa6x[MBa6x] U-Boot > usb start
TQMa6x[MBa6x] U-Boot > usb storage
TQMa6x[MBa6x] U-Boot > usb dev
TQMa6x[MBa6x] U-Boot > usb part
TQMa6x[MBa6x] U-Boot > fatls usb 0:1
TQMa6x[MBa6x] U-Boot > ext2ls usb 0:1
root@MBa6x:~ dmesg | grep -i usb
If a USB device is inserted after booting, the kernel will automatically provide information about the recently connected device. Thus one can easily read which device is to be used for mounting. The first partition of the device is sda1.
root@MBa6x:~ blkid
root@MBa6x:~ mount /dev/sda1 /mnt/