Rooted ZE551ML pre-image

I've follow instrucctions from this site to flash rooted pre-image to my phone:



http://ift.tt/1GIsgOY



But no luck, I'm stucked after enter "flash system system.img" get <waiting for device> for ever, any idea how to continue?

from xda-developers http://ift.tt/1J1e5BK

via IFTTT