After updating to 5.1.1 it keeps saying no sim and can't find my Optus sim card

Has your phone been hacked or jailbroken?

I had this issue. The only fix was to get a new sim (for $25 from Optus - thanks Optus). Worryingly, the no sim message reappeared briefly last night, but disappeared after power on/off

Probably not a coincidence - my iPad 3g microsim (also from Optus) has stopped working too after the upgrade. It did work initially, but now give a "No cellular data" message. Optus can't find a problem with it. So it looks like I need to replace that too.

This happened to me too.

No need to buy a new SIM. Just reset the handset by simultaneously pushing on/ff and home button. need to hold them down until phone goes off then on again. SIM successfully restored!

Switching off wifi, then going into airplane mode, power cycling, switching off airplane mode allowed my device to find optus. Finally switched on the wifi, all appears to be working as it should again.

Thanks so much Jeff that worked ..excellent fix ..

I tried Jeff's recommendation and it didn't work straight away.

I did about 3 or 4 hard resets though and magically I have my optus signal back again.

Strange...

I have had exactly the same problem! I just updated my Iphone 4 with the most recent software (like it kept wanting me too) and once I did that and detached it from my computer it now says No SIM, I have removed the Sim card, turned it on and off, tried airplane mode (all numerous times) and nothing is working!

Please help!! I am so frustrated because it worked completely fine before this update!

I did this and found network signal back again , BUT it doesn't work, sometimes working and sometimes not working, what should I do NOW.

i think you should replace a new sim card. maybe the sim card already corrupt.

Hi,

I did this with other phone operator as well but no improvement. please help some one to ged rid off.