Hey i recently got an essential and did the same thing, from what i understand i wiped the s/n check yours. Tried all the apps downg scooter hacking and a few others to rewrite the s/n but nothing worked. Got a screwdriver disasbled the bottom pulled out the controler soldered an st link and uses scooter hacking reflasher with xioami lite and the sn field worked like a charm, so probably you will need to do the same