Backing up the /sdcard of a Galaxy Nexus

After a long wait 4.0.4 is finally out for the Galaxy Nexus.I wanted to do a fresh install. I saved some important stuff using Titanium Backup, but I then needed to backup my data that shows under /sdcard.

After fighting with broken MTP on Ubuntu and even on Windows, I ended up doing a partition image using the dd command on an USB stick connected with an OTG cable:

mkdir /data/USB
 mount -rw -t ext4 /dev/block/sda1 /data/USB
 dd if=/dev/block/mmcblk0p12 of=/data/USB/SD.img