6670,7610 phone start up failed contact the retailer solved vit J.A.F
1)1st connect yu mobile vit jaf
2)if yur mobile not turn into local mode right side ther vil b a phone mode.there select local mode nd connect it vil connect.
3)then open imei tool nd click make ask rpl den click unlock.
den yur mobil vi b k
tested by me.
but 1st i did full flash erase vit hwk den flashd nd writen pm.after that i connect vit jaf nd i did given step 1 2 3.