Flashing raspberry pi OS to USB drive

Booting from USB drive

dd bs=4M if=2017-01-11-raspbian-jessie.img of=/dev/sdd






The SD card might be bigger than the original image
dd bs=4M if=/dev/sdd of=from-sd-card.img

truncate --reference 2017-01-11-raspbian-jessie.img from-sd-card.img

diff -s from-sd-card.img 2017-01-11-raspbian-jessie.img