DFU & Beaglebone black


I want to test DFU over usb to clone my beagle ( I don’t have a eMMC on this version )

u-boot side :

U-Boot# mmc part

Partition Map for MMC device 0 – Partition Type: DOS

Part Start Sector Num Sectors UUID Type
1 2048 3479552 00000000-01 83 Boot

but how I can start DFU over usb ? I looked up at some example :

U-Boot# dfu <module number>

but i don’t know what to put as module number ? what is my module number for the sdcard ? mmc 1 ?