Sometimes when I use dd then sync or use dd with conv=fsync, the syncing process gets stuck, but sometimes not, with exactly the same input and output targets and configuration.
dd if=2016-03-18-raspbian-jessie-lite.img of=/dev/sdg conv=fsyn
sync # freeze here
or
dd if=2016-03-18-raspbian-jessie-lite.img of=/dev/sdg conv=fsync
I experienced this inconsistent behavior on different distros like Ubuntu, Linux Mint (long time ago) and now on Gentoo and 4 different different machines.
