a)You must use Read information Button to see which version of phones you have .
b)If your phone is From April to June 2011 phone so flash is "8-mb" .Flash with 8 mb file"ZTE-S1602_V.MTS.S1602.B01_July_locked_8Mb.bin".
c)You must not do any other operation while flashing phones .
d)Phone is auto powered so avoid using battery to power on phones use Good qwality Usb Cabel.
e)Must remeber if your PC is hang or software get closed due to some unavoidabel Reasons phone will be dead.
f)Once phone Dead you need Flash programer to revive phones our tool not support Dead phones
g)If you are ok with all above points then you can try flash operation .
h)Purpose of flashing is to Repair phones other purpose you do at your own Risk .