iphone 3gs baseband 06.15.00 on ios4.1 want to upgrade to ios5 or 6

princexiaomi
princexiaomi Posts: 1
edited October 2012 in iPhone Forum
hello,I hope somebody can help me here.
I have an iphone 3gs by the following details
version : 4.1 ( 8b117)
modem firmware : 06.15.00
model : mc131hb
shsh:2381660675444

i want to upgrade to higher ios version, because recently can see less support on 4.1 and i am losing many apps and updates so i was searching for a way to upgrade to 5.1 or 6 or even 4.3 !

a guy told me baseband 06.15.00 cant be upgraded to higher ios .
but what i found in internet is maybe i can change my baseband through some tools!?

another guy told me that i cant update because after i checked on redsnow ECIDs 2381660675444 . he said the SHSH is not valid or so , and i cant upgrade because i can not unlock simcard later .

but i read on internet that i can do it by ultrasnow.


anybody knows how to help me!?
thanks a lot !