use infinity cdma tool v 1.89
1.Put orignal Ruim card and insert this code *983*87274#
2.Enable All fuctions clicked
3.Install all drivers
4.switch off phone and put Ruim which you want to use..
5.switch on phone it will have error message invalid card..
6.Select ZTE Handset Diagnostic Interface port..
7.CLick sp unlock..
Each Ruim which you want to use must be bind with phones..
here is driver