Hy! i have the "invalid sim" problem. my version of software is 9B179 and i don't know how to download the A version . pls help

Regarding the version of iOS, you have the correct version for iPhone 4S, that is version 5.1 (9B179). I don't know what you are referring to by "A version".

Regarding "invalid SIM", did it appear after you updated the phone to version 5.1? If yes, are you using the same carrier SIM card which originally came with the phone?

Take out your SIM card and insert it again. If you still see the invalid SIM message, try using another SIM card from the same carrier and see if it works. If it does, replace your SIM card.

Kadru wrote:

yes. it appear after the update. and yes i am using the same sim card that originally came with the phone.

If the problem appeared after an update and the phone had been jailbroken before the update that would explain your problem. If that is the case there there is no easy solution.

Replace the SIM and it should work.

Good luck..!

You are welcome.