Modify dfu-util For Ubuntu 14.04
#Inside your home directory, download dfu-util
git clone git://git.openezx.org/dfu-util.git
open dfu-util/src/dfu_load.c
add this instruction "milli_sleep(200);" under line 134
cd dfu-util
./autogen.sh
./configure
make
The resulting binary is dfu-util/src/dfu-util.