Successfully jailbreak(tethered) unlock 3GS version 6.1.3

Yesterday I successfully jailbreak n unlocked iphone 3GS on version 6.1.3 with baseband version 6.15(ipad baseband)...

-restore ur phone with 6.1.3 custom firmware.
-open latest redsn0w(redsn0w_win_0.9.15b3).
-goto to extras tab.
-click on "select ISPW".
-select 6.0
-go back
-click jailbreak
-follow the steps to enter DFU mode, once the process is done...
-again open redsnow n go to extras tab
-again click on "select ISPW"
-select 6.0
-then click on "just boot"
-follow the steps to enter DFU mode.

Once the above process is done, u will find cydia on ur phone, open cydia n install ultrasn0w 1.2.8. U will have ur phone unlocked.

This is a tethered jailbreak

If ur phone is searchig for network even without the sim card after the above process then simply install the ipad baseband again n it will work fine...

BR