I have an iPhone 3g and I'm trying to downgrade it from 4.2.1 to 3.1.3.
I downgraded it successfully and use redsn0w to boot it. It is factory unlocked by itunes, but it seems like it's not getting any signal though. Is it because that I have a baseband of 06.15.00? But how do I downgrade it if that's the issue?