Finally my wife ip4 IOS phone has experience the probs as u guys mentioned here.try all sorts of hard reset,sim card out,airplane mode,reset network settings etc seems not working.the phone can receive/call out but no sound at all,and SMS not received. Funny thing is what's app working fine for us to communicate.gotta go home early to sort out the probs.

No resolution on this yet? God helps us! Getting more and more frustrated!

Do a restore and don't restart/close ur phone if possible, just charge before it gets empty. I notice the problem comes back after frequent reboots.

Done that for quite some times. Problem recurs in 3 to 4 days. I wonder 4S will have similar issue.

demit...happened again after restore it

Which shop to sent it? is it 3GS or iP 4?
I thot I have the same problem, worst is I manually chnage to iPad baseband and dont find the method to undo it.
I'm willing to pay if there are anyone who can fix my iP 3GS. or at least help me find the expertise shop.

I did go to lowyat, 3 shops, none of them seem to know what baseband is and they keep found error on itunes restoring it. -__-" noobies i think.

3gs ios5 using ipad baseband must use ultrasnow 1.2.4,ultrasnow fixer and use cydia v1.1.2 not a v1.1.1..

Already have the solution? I restore my phone once a week! Wasting time.

wow guess i'm not the only 1 too... mine is a iPhone 4 on 5.0.1 jailbroken semi-untethered, did a search on google and found out a quick fix just on and off cellular data,wait a few minutes and viola! My phone ori firmware is 4.1.3(NO SAVE SHSH cause too late),wanna try iOS 5 so i upgraded,my 1st impressions was the battery life actually lasts longer than my previous firmware (weird i heard so many people complain about battery life on iOS 5) and 2 weeks now no service struck me.....well need a permanent fix don't want to reboot,reset network and restore...

Temporary solution :

Just keep reseting : from reset all settings if that doesn't work, reset network settings, rinse and repeat if doesn't work at each reset.

Its pretty stable after several resets when problem recurs, even found back the lost signal after coming out from the lift.

Or just downgrade to iOS 4 if u got SHSH blobs saved. I was lucky

4s can downgrade ker?? huhuhu..this things happen to me this morning...beli beribu sms n call xmasuk!!

I tried restarting then only it worked. iOS 5.0.1 9A405 on iPhone 4S. This totally sucks.

sames goes to me .. but i always face issue like my 3g will dissappear if i go into the lift and come out. i see my maxis coverage full bar.. but my 3G not there.. but go setting its on. and if i off and on again still no sign.

only need to reset network setting all the time.. so troublesome.. any way to help me?

I experienced the same thing upon upgrading my 3GS. SIM not valid. Tried calling Maxis about it, they say that we should restore to stock condition of iOS 4 first before we upgrade to iOS 5. The Maxis technician must be stupid to even suggest that! (Now I know Maxis technicians are stupid)

Only solution for me is to use sn0wbreeze and select "unlock" in the expert setting! That leaves me no choice but to jailbreak it! Really kanas@i larr .....

This post has been edited by jackyyong: Dec 27 2011, 04:44 PM

This morning I try to turn on Cellular Data on my 4S. But it seem it is not working. It doesn't appear either E or 3G symbol until i restart my phone. Only that the switch is working..

using 4s here...so far dont have this problem, just when from car park to outside, its take sometimes to search the services, but i tot this is common for iphone...

is this problem covered within the warranty? has anybody check with maxis?

Just ask u to reset network settings. Don't think its covered since we all agreed its the problem with IOS 5. not the hardware

any permanent solution to this problem?? having same problem also here..

has anybody tried jb, will problem this solved after jb?