title: u-boot flash emmc ttl serial
body: <p>I used to update firmware on embedded system through tools like tftp (with ethernet port or ethernet over usb), sd card  or a simple usb stick.</p>
  
  <p>I am currently working on a system without ethernet port, no usb port. Only a ttl/usb connexion to be able to access the console and a micro usb to supply it. I am currently building a linux image and a rootfs. The storage used on the board is emmc.</p>
  
  <p>Is there a standard way to update linux/rootfs in Emmc, etc.. with u-boot by using a simple ttl/usb connexion ? I guess that I can part my flash in u-boot thanks to mmc command but I don't understand how to transfer my kernel image and my rootfs in emmc with a simple ttl/usb link.</p>