Unable to use wifi on iPhone3G after update to iOS 4.0.1

[Svana]

I have freshly updated my iphone 3GS to iOS 4.0.1 from 4.0 version. After successful upgrade I get everything working properly except wifi. It was fine before the upgrade. But suddenly the wifi signal dropped and till now unable to fix it. I have tried it by altering the settings manually but didn’t make it work. Restarted my phone and trying to connect different devices but couldn’t able to establish connection. Still I am seeing the wifi as a dropped in signal. What do you say about this? Is there any fix for this issue? I hope that I wouldn’t update to latest version until I confirm it from some known persons or users.

[AzzamKhan]

I have upgraded my iphone to this version but I didn’t get any issue. Everything works better than before, in fact faster too. I think that update wasn’t successful enough and incomplete update may cause these kinds of cause in apps. After upgrading there is a reboot process for Iphone. I think you may aware about it. There is Hard reboot by holding down power button and Home button. Keep them holding down until you get the reset screen several times. If it is not doing by these combinations then let it go. This feature hasn’t included in your model. Reboot will reset the entire phone to its default settings.

[Mariah-Simpson]

For me it seems to me that the phone locked up the wifi signal. For this reset network settings on your iphone. To do this open Settings> General>Reset>” Reset Network Settings”. This option will delete all information along with passwords and enables the stable connection between 2 wifi. If this didn’t works then you need to reset the whole phone to its default settings.

[Amma-Watson]

There is one small possible fix less than ideal for your wifi issue. It is about restoring your phone as a fresh device other than from the source of backup. But there are several drawbacks by performing this process. You will loss all the data including contacts, messages and all other information but usually this will resolve 90% problem as my concern. To do this you will need computer connected to your iphone and latest version of iTunes installed on it. Launch iTunes and assume that your phone is properly recognized by it. Click “Restore> setup as new phone”. This will take a while to make a new device.

[KennedII]

How can you say that it is the cause of the latest ios? Why it can’t be the Hardware issue? Did you show it to apple service store to ensure the functioning of hardware components? In phone settings left of the Wifi how the icon is appearing? Is it colored or just a grey? Switch on the Wifi and again notice the log? If it changed to color then there is not much problem. If it is still grey even after Turn On then you need to worry about it. Can able to downgraded the ios? If yes, do it now and see whether you are able to getting signal or not.