Iphone 4 and wifi problem

I have been using my iphone 4 with my wifi connection at home for months now. All of a sudden it asked me for the password and consistently tells me its incorrect. I know its not, i use it to connect from my imac and macbook pro and it works. I use the airport extreme router and broadcast in standard and 5ghz for my atv2.
I have reset the network, restored my iphone, changed every possible setting i could and yet still it tells me the password is invalid, i have no idea why all of a sudden this would become a problem. I have not changed anything on the phone, i am on ios 4.2.1 and i have been for awhile. I jailbreak so i dont want to upgrade to 4.3 yet but i dont see why that would cause an issue, i have tried to access wifi both jailbroken and not and still nothing. Could this be a hardware issue, i dont know what else to try.
iPhone 4 AT&T iOS 4