I try this :
sudo dd if=2016-07-21-ubuntu-mate-16.04-desktop-armhf-raspberry-pi-bpi-m3-sd-emmc.img bs=1M of=/dev/mmcblk0
And i have this on result :
7456+0 enregistrements lus
7456+0 enregistrements écrits
7818182656 bytes (7,8 GB, 7,3 GiB) copied, 775,056 s, 10,1 MB/s
But same problem. Auto shut down after 3 seconds (bpi logo screen)