Recebi esse tutorial de um gringo. Eles também estão tendo o mesmo problema. A apple não fala nada porque provavelmente vai esperar até ter motivos suficientes pra lançar a versão 5.02, independento do que estamos pensando. Infelizmente. As operadoras parece que não sabem a causa. Parece que as antenas ficam presas.
Ainda não tinha visto esse. Os outros já tentei todos e nada.
if u r facing sudden "Network searching/ No Service/ Invalid Sim/ Call Failed.." issues after iOS 5.0.1 update with any GP/ Banglalink/ Robi sim(s).. then.. 1. buy an AIRTEL 64k regular sim card.. 2. hand cut it to a micro sim & put it in ur iPhone 4s.. 3. Reset your Network settings from Settings> General> Reset> Reset Network Settings.. 4. after ur iPhone reboots, make sure your carrier setting is set to "Automatic", sim pin is "disabled", caller id is "on", call waiting is "on"..
and YAHOOO.. ur iPhone is all set to run as healthy as it is.. No more problems with the Network/ Sim/ Receive or Making Calls/ Sending text messages.. blah blah :).. I had the same 7 days problems with my GP/ ROBI sims as those were not working with the new iPhone 4s but were working absolutely fine with my iPhone 4.. then I started using AIRTEL sim and TADA! I'm not facing any sort of problem with my iPhone 4s anymore for d last 24 hours & it also solved the battery issue as well! (Cause d more time it'll search for "Networks", the more % of battery u'll lose!)
And if u want to c ur own phone number under the Phone settings, then 1st connect to wifi connection, then activate iMessage (it'll ask ur itunes id & password, so fill those up), then activate Facetime (it'll ask ur itunes id & password, so fill those up).. after doing these successfully u'll c ur own phone number for sure :)..
Knock me up if u need any further help.. (Sorry for such a long tut!)