there is some other hard ways to solve the problem... by doing a clean restore and upgrade then JB it....

i know most of u guys dont like this alternatives.. but it works for me.

logical explaination? maybe there's something wrong with the setting when u upgrade it or some files missing or god knows wht happened inside the iphone which concluded the lines drops, wifi not working etc..

this is 1 of the way u can resolve the problem... but this is an option... u can go for other methods.

but this is one of the method i used if my iphone start behaving like tht...
its pain staking... yeah... but it worked... well for me...

clean restore= on ur itunes click the restore button without holding the shift button.... a massage will appear asking if u want to upgrade ur phone to latest FirmWare, just click yes and wait for the magic to happen.

then Pwn it and tick unlock ( iguess u understand this) bla.. bla.. and done....!!!

give it a try and make us proud!
hohohoho