1= A iPhone 3gs with supported bass band for unlock with ultrasnow.
4= redsn0w_win_0.9.15b3 or later version
Before starting be very careful do full backup of your phone using iTunes. also save SHSH blobs using redsnow to revert back to your current version of ios.
This method is tested by me and working.you see in pictures. do at your own risk i am not responsible of any damage or any mistake during this work.
after doing backup of your device.
connect iphone with pc and open redsn0w_win_0.9.15b3 then go to Extra > Even more > Restore
and select iPhone2_1_6.0.1_10A523_Restore.ipsw redsnow prompt you that redsnow doesn’t recognize this ipsw but it can still prevent a bassband update select yes.
redsnow will process ipsw and then restore to iphone this will tack more then 10 minutes approx to complete this possess.
now you need to jailbreak this phone to get working
open redsn0w_win_0.9.15b3 then Extras and select ipsw and select
iPhone2_1_6.0_10A403_Restore.ipsw Now go back and press jailbreak.
and follow the instruction given by redsnow. this will complete in few minutes. after this possess complete you will see phone in working condition but when you press cydia it will close immediately don.t worry.
now open redsnow again and press Extras and then Just boot (just boot tethered right now) after this phone will be normal cydia and other apps will work now.
now go to cydia and add source pointed in picture. and install ultrasnow and ultrasnow fixer.
after installing ultrasnow and ultrasnow fixer phone should be unlocked. if still searching just reinstall ultrasnow. phone will recive network signals now.
This is tethered jailbreak because untethered jailbreak for ios 6.0.1 is not yet released.
So Good Luck all of you friends who give some time to read this.