iPhone 3G / Wifi problem / 4.2.1

I spent the last 2 hours trying to solve the Wifi connection problem introduced with 4.2.1.
The problem in my case: The Wifi password is not accepted. Even disabling the security doesn't help.
I tried:
Router reset, waiting 20 min - nope
Iphone wifi settings reset - nope
Changed channel from 6 to 7 - nope
Router firmware update - nope
Wifi password change - nope
Wifi security change (disabled) - nope

So thanks Apple for this glorious update and for the fun time I had!
This was my last IPhone OS update, I had several similar problems in the past. But one of the above steps always worked - after several tries ...
(fyi - the Airport Connection on my MacBook Pro works without problems)

Encryption passwords are case sensitive. In addition if you make a mistake with the input and backspace to remove the error this procedure does not work. You need to input the password from start to finish entirely without any errors. Ant..

Thanks for your help, but unfortunately this wasn't the solution.
I also seem to have the same battery problem (introduced with 4.2.1) as several other users - this was the worst update I ever experienced.
Even a general settings/reset doesn't help ...

Im away on holiday at the moment and cant connect to my mates wifi.

Is there any solution to this yet as it would be handy if i could get it working.

Have apple launched a repair for it or anything? not that i can update anyway as i dont have itunes on my friends PC

grrr

News? ._.

Hi GinoLoSpazzino. What have you done to try and connect also describe the symptoms Ant..

i read on some other forum where an application called "WiFiFoFum" fixed the wifi issue for a few users.

you could try some other utilities available on app store that search for WiFi connections and let you set/reset some of the scan frequencies etc. Play around with it and see if that helps

Hi GinoLoSpazzino if you go to www.vistumbler.net they have available some 'Free' software that runs in Vista designed to Scan and Report on Wireless Networks. It will show you how many Routers using the same channel are in close proximity, what your signal strengths are etc. It will help you eliminate the router as the point of failure. I am not associated with vistumber in any way and this is not an endorsement of their product. Ant..

So I spent another 2 hours and tried the backup & restore solution. No way, doesn't work either. This was my last hope, I run out of options.

Hi Derrick13 consider the option set out in the previous post.. and eliminate the router as the point of failure.. Ant..

adnixon @ AP & Router are ok :

Powerbook G4 Work
MSI GT627 Work
EEEPC 900 Work

Hi GinoLoSpazzino. Ok so you have convinced yourself that it is not the Router that being the case take the phone to a 'Free' hotspot and try and establish Wi-Fi connectivity. In Australia that would be a Macdonalds Restaurant. If you get the same symptoms with the phone then it will be an issue with the phone. That being the case I would approach and ask the vendor to provide you with the solution. Ant..

I Have The same problem with my iphone 3g 4.2 !!! What`s up??? i need my wifi =( pleaaaaaaaaaaaseeee help porfavor ayudemen no funciona el wifi de mi iphone 3g 4.2