iPhone 3G iOS 4.2.1 No Wi-Fi and No Service after downgrade from 06.15.00 to 05.13.04
I have an iPhone 3G with jailbroken iOS 4.2.1 on it. I read an older article and installed 06.15.00 iPad firmware in order to unlock it so I can use it for what it should be (a phone). It had major battery drain issues and GPS was not working (the default problems), so I searched around some more and found out that the baseband can actually be downgraded from 06.15.00 to 05.13.04 now, so I went at it. The first try did not succeed and I was still on 06.15.00 after trying to downgrade it with redsn0w 0.9.14b1, I reinstalled the 06.15.00 baseband and tried downgrading it again with the newest redsn0w 0.9.14b2 version. This time I succeeded.
However, now in the information section by Modem Firmware it was completely blank, but I knew that this time it downgraded, since it didn't show 06.15.00 anymore, so that counts for something, right?
Here is the problem though, now I get no signal, and my phone says no wi-fi also. I have read that the no signal problem can be fixed by reinstalling ultrasn0w and Mobile Substrate, but I can't do that with both no signal and no wi-fi.
What are my options here?