Trying restore to 4.0.1 to get wi-fi back; need answers

[HAL1275]

I lost wi-fi on my 3g for no apparent reason; I still detect wi-fi, just can't join networks (the network information screen displays blanks in all fields). I am currently running iOS 4.0.1 jb with jailbreakme.com. I want to do a restore to new iPhone to attemp to get wi-fi back, but how do I do this without being forced to update to iOS 4.0.2? Any help or answers would be appreciated. Before anyone asks, yes, I have tried Apple's official method, as well as shutting off the 3G & wi-fi and clearing network settings, to fix the wi-fi issue, all to no avail.

[PSI70Y]

back up your SHSH blolb using tinyumbrella as I think Apple are still signing 4.0.1. This means you will always be able to go back to 4.0.1 to restore