Jailbroken 3G with IOS 4 and no wifi - what to do?

[msr2k]

I've been using my iPhone 3G with IOS 2.0.2 and turbosim on T-Mobile and foolishly decided to upgrade to IOS 4.0 / 05.13.04 baseband
I Jailbroke it with RedSn0w but I can't make much progress in unlock because wifi is not working anymore (does not discover networks, when I enter SSID/password manually it says 'cannot scan for wireless networks'). Turbosim is not working with the new baseband so I can't make calls.

(1 hour later - found solution!)

I found a simple solution posted by CincinnatiKid here: WiFi issues on iOS4 - iPhone 3G - redsn0w JB

Basically, there is a PC version of Cydia called Cyder. I downloaded the needed packages on my PC and transferred to the iphone via USB cable. It took me 5 minutes to do the whole thing! Here are the detailed instructions:
How to Unlock iPhone 3G/3GS with iOS 4 using ultrasn0w 0.9.3 without WiFi with Cyder [Guide] | Apple | iThinkDifferent

[nebo1ss]

Thanks for your post it will be useful. I had a similar problem as yours with
a 3G last week and found that if i stood next to the router the wifi worked. So was able to do the unlock. It seems the 3G issue on wifi is signal level related.