Possible solution to the wifi problem!!!!!! READ THIS!!
guys! i had the same problem with mi wi-fi but after pushing buttons it worked!
this is the sequence of buttons and tasks i did...(iphone 3gs fw 3.1.2 updated bootrom)
1:turn off iphone run blackra1n and do not touch anything just keep the final dialog intact and the program open (initial thethered boot)
2:airplane on / wifi off
3: turn off by sliding....(reset with home and power?) i didnt test...
4:with the phone still attached to the computer i turned it on wit for the itunes logo and then pressed the blackra1n window that says the iphone was ready to be used and all that stufff (on the pc) somehow the pic of geohot apeared on the phone but it was doing nothing.... and the program said "waiting for device"... so i waited a little the i turned off my phone and then i turned on so it started to boot with blackra1n (thethered) then the iphone booted up and voila! wifi back on business!!!!!....
try for yourself! if it works then we have a "solution" to spread to the rest of the people! see yaaaa hope it works!!!!